### Is there an existing issue for this?

- [X] I have searched the existing issues

### Current Behavior

If the Lambda returns an error, the message is put into DLQ straightaway after first try **although** the configurations says "try 3 times".

### Expected Behavior

If the Lambda returns an error, the message should be put into DLQ after what `RedrivePolicy.maxReceiveCount` says which is 3 in this case. For instance, try processing the message 3 times, if still no success, put it into DLQ.

### How are you starting LocalStack?

With a docker-compose file

### Steps To Reproduce

```yaml
version: "3.8"

services:
  localstack:
    image: "localstack/localstack"
    container_name: "localstack"
    ports:
      - "4566-4599:4566-4599"
    environment:
      - DEBUG=1
      - DEFAULT_REGION=eu-west-1
      - SERVICES=lambda,events,sqs
      - DATA_DIR=/tmp/localstack/data
      - DOCKER_HOST=unix:///var/run/docker.sock
      - LAMBDA_EXECUTOR=docker
    volumes:
      - "./tmp/localstack:/tmp/localstack"
      - "/var/run/docker.sock:/var/run/docker.sock"
```

### Environment

```markdown
- OS: MacOS BigSur
- LocalStack: `1dc090777b0c`
```


### Anything else?

This will try **only once** and put the message into DLQ after failure **although** the retry policy instructs for **3 retries**. This is the issue.

```bash
aws --profile localstack --endpoint-url http://localhost:4566 lambda create-function \
    --function-name api-lambda \
    --handler lambda/main \
    --runtime go1.x \
    --role api-role \
    --zip-file fileb://lambda.zip
    
aws --profile localstack --endpoint-url http://localhost:4566 sqs create-queue \
    --queue-name api-dead-letter-queue

aws --profile localstack --endpoint-url http://localhost:4566 sqs create-queue \
    --queue-name api-queue \
    --attributes '{"RedrivePolicy":"{\"deadLetterTargetArn\":\"arn:aws:sqs:eu-west-1:000000000000:api-dead-letter-queue\",\"maxReceiveCount\":\"3\"}"}'

aws --profile localstack --endpoint-url http://localhost:4566 lambda create-event-source-mapping \
    --function-name api-lambda \
    --event-source-arn arn:aws:sqs:eu-west-1:000000000000:api-queue
```

Use this command to test.

```bash
aws --profile localstack --endpoint-url http://localhost:4566 sqs send-message \
    --queue-url http://localhost:4566/000000000000/api-queue \
    --message-body '{"hello":"world"}'
```

----

FYI - This will try **indefinitely** (_30 sec in between_) until it succeeds because there is **no** retry policy set which is perfectly normal and expected behaviour.

```bash
aws --profile localstack --endpoint-url http://localhost:4566 lambda create-function \
    --function-name api-lambda \
    --handler lambda/main \
    --runtime go1.x \
    --role api-role \
    --zip-file fileb://lambda.zip
    
aws --profile localstack --endpoint-url http://localhost:4566 sqs create-queue \
    --queue-name api-dead-letter-queue

aws --profile localstack --endpoint-url http://localhost:4566 sqs create-queue \
    --queue-name api-queue

aws --profile localstack --endpoint-url http://localhost:4566 lambda create-event-source-mapping \
    --function-name api-lambda \
    --event-source-arn arn:aws:sqs:eu-west-1:000000000000:api-queue
```
func_name = lambda_function.name()
        url = "%s%s/functions/%s/invocations" % (forward_url, API_PATH_ROOT, func_name)
        copied_env_vars = lambda_function.envvars.copy()
        copied_env_vars["LOCALSTACK_HOSTNAME"] = config.HOSTNAME_EXTERNAL
        copied_env_vars["LOCALSTACK_EDGE_PORT"] = str(config.EDGE_PORT)
        headers = aws_stack.mock_aws_request_headers("lambda")
        headers["X-Amz-Region"] = lambda_function.region()
        headers["X-Amz-Request-Id"] = context.aws_request_id
        headers["X-Amz-Handler"] = lambda_function.handler
        headers["X-Amz-Function-ARN"] = context.invoked_function_arn
        headers["X-Amz-Function-Name"] = context.function_name
        headers["X-Amz-Function-Version"] = context.function_version
        headers["X-Amz-Role"] = lambda_function.role
        headers["X-Amz-Runtime"] = lambda_function.runtime
        headers["X-Amz-Timeout"] = str(lambda_function.timeout)
        headers["X-Amz-Memory-Size"] = str(context.memory_limit_in_mb)
        headers["X-Amz-Log-Group-Name"] = context.log_group_name
        headers["X-Amz-Log-Stream-Name"] = context.log_stream_name
        headers["X-Amz-Env-Vars"] = json.dumps(copied_env_vars)
        headers["X-Amz-Last-Modified"] = str(int(lambda_function.last_modified.timestamp() * 1000))
        headers["X-Amz-Invocation-Type"] = invocation_type
        headers["X-Amz-Log-Type"] = "Tail"
        if context.client_context:
            headers["X-Amz-Client-Context"] = context.client_context
        if context.cognito_identity:
            headers["X-Amz-Cognito-Identity"] = context.cognito_identity
        data = run_safe(lambda: to_str(event)) or event
        data = json.dumps(json_safe(data)) if isinstance(data, dict) else str(data)
        LOG.debug(
            "Forwarding Lambda invocation to LAMBDA_FORWARD_URL: %s", config.LAMBDA_FORWARD_URL