### Is there an existing issue for this?

- [X] I have searched the existing issues

### Current Behavior

Using the serverless framework, when deploying a lambda function that uses a custom container runtime, the image is pushed to localstack with an "ImageUri" value that includes the docker image's digest (e.g. `localhost:4513/serverless-test-local@sha256:306d92[TRUNCATED]`). When executing that lambda function, fullstack uses the docker url that includes the digest, and improperly treats the portion after `:` as an image tag (https://github.com/localstack/localstack/blob/master/localstack/utils/docker_utils.py#L1203), causing the function to fail.

### Expected Behavior

Localstack should pull the docker image with the properly formatted digest and successfully execute the lambda function.

### How are you starting LocalStack?

With the `localstack` script

### Steps To Reproduce

#### How are you starting localstack (e.g., `bin/localstack` command, arguments, or `docker-compose.yml`)

    localstack start

#### Client commands (e.g., AWS SDK code snippet, or sequence of "awslocal" commands)
Sample serverless.yml
```
service: test
plugins:
  - serverless-localstack

frameworkVersion: '2'

provider:
  name: aws
  lambdaHashingVersion: 20201221
  ecr:
    images:
      test:
        path: ./test

custom:
  localstack:
    debug: true
    stages:
      - local
    host: http://localhost
    edgePort: 4566  
    autostart: true 
    docker:
      sudo: False

functions:
  test:
    image:
      name: test
```

Execute function
```
sls deploy --stage local
awslocal lambda invoke --function-name test-local-test /dev/null
```

Localstack error
```
2021-11-08T19:25:08:INFO:localstack.services.awslambda.lambda_executors: Running lambda: arn:aws:lambda:us-east-1:000000000000:function:test-local-test
2021-11-08T19:25:08:DEBUG:localstack_ext.services.awslambda.lambda_extended: Putting invocation event (request ID d01c1e28) for Lambda 'arn:aws:lambda:us-east-1:000000000000:function:test-local-test' to queue
2021-11-08T19:25:08:DEBUG:localstack_ext.services.awslambda.lambda_launcher: Executing custom image execution for image localhost:4513/serverless-test-local@sha256:306d925cd4f0188bcb9808c7715fc444dff3eee356415e58651db25304825221
2021-11-08T19:25:11:DEBUG:localstack.utils.docker_utils: Pulling image: localhost:4513/serverless-test-local@sha256:306d925cd4f0188bcb9808c7715fc444dff3eee356415e58651db25304825221
2021-11-08T19:25:11:DEBUG:localstack.utils.docker_utils: Repository: localhost:4513/serverless-test-local@sha256 Tag: 306d925cd4f0188bcb9808c7715fc444dff3eee356415e58651db25304825221
2021-11-08T19:25:12:ERROR:localstack_ext.services.awslambda.lambda_extended: Unable to invoke Lambda "arn:aws:lambda:us-east-1:000000000000:function:test-local-test": 
Traceback (most recent call last):
  File "/opt/code/localstack/.venv/lib/python3.7/site-packages/docker/api/client.py", line 268, in _raise_for_status
    response.raise_for_status()
  File "/opt/code/localstack/.venv/lib/python3.7/site-packages/requests/models.py", line 943, in raise_for_status
    raise HTTPError(http_error_msg, response=self)
requests.exceptions.HTTPError: 404 Client Error: Not Found for url: http+docker://localhost/v1.41/images/create?tag=306d925cd4f0188bcb9808c7715fc444dff3eee356415e58651db25304825221&fromImage=localhost%3A4513%2Fserverless-test-local

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/opt/code/localstack/localstack/utils/docker_utils.py", line 1208, in pull_image
    self.client().images.pull(repository, tag)
  File "/opt/code/localstack/.venv/lib/python3.7/site-packages/docker/models/images.py", line 447, in pull
    repository, tag=tag, stream=True, all_tags=all_tags, **kwargs
  File "/opt/code/localstack/.venv/lib/python3.7/site-packages/docker/api/image.py", line 430, in pull
    self._raise_for_status(response)
  File "/opt/code/localstack/.venv/lib/python3.7/site-packages/docker/api/client.py", line 270, in _raise_for_status
    raise create_api_error_from_http_exception(e)
  File "/opt/code/localstack/.venv/lib/python3.7/site-packages/docker/errors.py", line 31, in create_api_error_from_http_exception
    raise cls(e, response=response, explanation=explanation)
docker.errors.NotFound: 404 Client Error for http+docker://localhost/v1.41/images/create?tag=306d925cd4f0188bcb9808c7715fc444dff3eee356415e58651db25304825221&fromImage=localhost%3A4513%2Fserverless-test-local: Not Found ("manifest for localhost:4513/serverless-test-local:306d925cd4f0188bcb9808c7715fc444dff3eee356415e58651db25304825221 not found: manifest unknown: manifest unknown")

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/opt/code/localstack/.venv/lib/python3.7/site-packages/localstack_ext/services/awslambda/lambda_extended.py", line 448, in do_run_lambda_executor
  File "/opt/code/localstack/.venv/lib/python3.7/site-packages/localstack_ext/services/awslambda/lambda_launcher.py", line 222, in docker_separate_execute_in_container
  File "/opt/code/localstack/.venv/lib/python3.7/site-packages/localstack_ext/services/awslambda/lambda_launcher.py", line 189, in custom_image_execute_in_container
  File "/opt/code/localstack/.venv/lib/python3.7/site-packages/localstack_ext/services/awslambda/lambda_launcher.py", line 148, in get_image_entrypoint_cmd
  File "/opt/code/localstack/localstack/utils/docker_utils.py", line 1212, in pull_image
    raise ContainerException()
localstack.utils.docker_utils.ContainerException
2021-11-08T19:25:12:INFO:localstack_ext.services.awslambda.lambda_extended: Lambda container output: None
None
2021-11-08T19:25:12:INFO:localstack.services.awslambda.lambda_api: Error executing Lambda function arn:aws:lambda:us-east-1:000000000000:function:test-local-test:  Traceback (most recent call last):
  File "/opt/code/localstack/.venv/lib/python3.7/site-packages/docker/api/client.py", line 268, in _raise_for_status
    response.raise_for_status()
  File "/opt/code/localstack/.venv/lib/python3.7/site-packages/requests/models.py", line 943, in raise_for_status
    raise HTTPError(http_error_msg, response=self)
requests.exceptions.HTTPError: 404 Client Error: Not Found for url: http+docker://localhost/v1.41/images/create?tag=306d925cd4f0188bcb9808c7715fc444dff3eee356415e58651db25304825221&fromImage=localhost%3A4513%2Fserverless-test-local

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/opt/code/localstack/localstack/utils/docker_utils.py", line 1208, in pull_image
    self.client().images.pull(repository, tag)
  File "/opt/code/localstack/.venv/lib/python3.7/site-packages/docker/models/images.py", line 447, in pull
    repository, tag=tag, stream=True, all_tags=all_tags, **kwargs
  File "/opt/code/localstack/.venv/lib/python3.7/site-packages/docker/api/image.py", line 430, in pull
    self._raise_for_status(response)
  File "/opt/code/localstack/.venv/lib/python3.7/site-packages/docker/api/client.py", line 270, in _raise_for_status
    raise create_api_error_from_http_exception(e)
  File "/opt/code/localstack/.venv/lib/python3.7/site-packages/docker/errors.py", line 31, in create_api_error_from_http_exception
    raise cls(e, response=response, explanation=explanation)
docker.errors.NotFound: 404 Client Error for http+docker://localhost/v1.41/images/create?tag=306d925cd4f0188bcb9808c7715fc444dff3eee356415e58651db25304825221&fromImage=localhost%3A4513%2Fserverless-test-local: Not Found ("manifest for localhost:4513/serverless-test-local:306d925cd4f0188bcb9808c7715fc444dff3eee356415e58651db25304825221 not found: manifest unknown: manifest unknown")

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/opt/code/localstack/localstack/services/awslambda/lambda_api.py", line 813, in run_lambda
    lock_discriminator=lock_discriminator,
  File "/opt/code/localstack/localstack/services/awslambda/lambda_executors.py", line 429, in execute
    return do_execute()
  File "/opt/code/localstack/localstack/services/awslambda/lambda_executors.py", line 419, in do_execute
    return _run(func_arn=func_arn)
  File "/opt/code/localstack/localstack/utils/cloudwatch/cloudwatch_util.py", line 158, in wrapped
    raise e
  File "/opt/code/localstack/localstack/utils/cloudwatch/cloudwatch_util.py", line 154, in wrapped
    result = func(*args, **kwargs)
  File "/opt/code/localstack/localstack/services/awslambda/lambda_executors.py", line 406, in _run
    raise e
  File "/opt/code/localstack/localstack/services/awslambda/lambda_executors.py", line 402, in _run
    result = self._execute(lambda_function, inv_context)
  File "/opt/code/localstack/localstack/services/awslambda/lambda_executors.py", line 710, in _execute
    result = self.run_lambda_executor(lambda_function=lambda_function, inv_context=inv_context)
  File "/opt/code/localstack/.venv/lib/python3.7/site-packages/localstack_ext/services/awslambda/lambda_extended.py", line 538, in run_lambda_executor
  File "/opt/code/localstack/.venv/lib/python3.7/site-packages/localstack_ext/services/awslambda/lambda_extended.py", line 436, in run_lambda_executor
  File "/opt/code/localstack/.venv/lib/python3.7/site-packages/localstack_ext/services/awslambda/lambda_extended.py", line 448, in do_run_lambda_executor
  File "/opt/code/localstack/.venv/lib/python3.7/site-packages/localstack_ext/services/awslambda/lambda_launcher.py", line 222, in docker_separate_execute_in_container
  File "/opt/code/localstack/.venv/lib/python3.7/site-packages/localstack_ext/services/awslambda/lambda_launcher.py", line 189, in custom_image_execute_in_container
  File "/opt/code/localstack/.venv/lib/python3.7/site-packages/localstack_ext/services/awslambda/lambda_launcher.py", line 148, in get_image_entrypoint_cmd
  File "/opt/code/localstack/localstack/utils/docker_utils.py", line 1212, in pull_image
    raise ContainerException()
localstack.utils.docker_utils.ContainerException
```


### Environment

```markdown
- OS: MacOS Big Sur 11.1
- LocalStack: 0.12.20
```


### Anything else?

_No response_
import json
import logging
import os
import platform
import re
import socket
import subprocess
import tempfile
import time
from os.path import expanduser
from typing import Dict, List, Mapping
import six
from boto3 import Session
from localstack.constants import (
    AWS_REGION_US_EAST_1,
    DEFAULT_BUCKET_MARKER_LOCAL,
    DEFAULT_DEVELOP_PORT,
    DEFAULT_LAMBDA_CONTAINER_REGISTRY,
    DEFAULT_PORT_EDGE,
    DEFAULT_SERVICE_PORTS,
    FALSE_STRINGS,
    LOCALHOST,
    LOCALHOST_IP,
    LOG_LEVELS,
    TRACE_LOG_LEVELS,
    TRUE_STRINGS,
)
load_start_time = time.time()
def eval_log_type(env_var_name):