### Is there an existing issue for this?

- [X] I have searched the existing issues

### Current Behavior

Starting localstack with the CLI `PROVIDER_OVERRIDE_SQS=asf bin/localstack --debug start` starts up correctly but then uses the `default` SQS provider.

### Expected Behavior

I would expect it to start the asf provider.

### How are you starting LocalStack?

With the `localstack` script

### Steps To Reproduce

* `PROVIDER_OVERRIDE_SQS=asf bin/localstack --debug start`
* `awslocal sqs create-queue --queue-name "test-queue"`

logs show:

```
2021-12-27T14:08:43.274:DEBUG:plugin.manager: instantiating plugin PluginSpec(localstack.aws.provider.sqs:default = <function sqs at 0x7f30e6d2b820>)
2021-12-27T14:08:43.274:DEBUG:plugin.manager: loading plugin localstack.aws.provider:sqs:default
2021-12-27T14:08:43.278:INFO:localstack.services.infra: Starting mock SQS service on http port 4566 ...
2021-12-27T14:08:43.279:INFO:localstack.services.infra: Starting mock SQS service on http port 4566 ...
2021-12-27T14:08:43.279:INFO:localstack.services.motoserver: starting moto server on http://0.0.0.0:38335
```

### Environment

```markdown
- OS: Ubuntu 20.04
- LocalStack: 13.2
```


### Anything else?

_No response_
"LAMBDA_DOCKER_NETWORK",
    "LAMBDA_REMOVE_CONTAINERS",
    "USE_SSL",
    "USE_SINGLE_REGION",
    "DEBUG",
    "KINESIS_ERROR_PROBABILITY",
    "DYNAMODB_ERROR_PROBABILITY",
    "DYNAMODB_READ_ERROR_PROBABILITY",
    "DYNAMODB_WRITE_ERROR_PROBABILITY",
    "ES_CUSTOM_BACKEND",
    "ES_ENDPOINT_STRATEGY",
    "ES_MULTI_CLUSTER",
    "DOCKER_BRIDGE_IP",
    "DEFAULT_REGION",
    "LAMBDA_JAVA_OPTS",
    "LOCALSTACK_API_KEY",
    "LAMBDA_CONTAINER_REGISTRY",
    "TEST_AWS_ACCOUNT_ID",
    "DISABLE_EVENTS",
    "EDGE_PORT",
    "LS_LOG",
    "EDGE_PORT_HTTP",
    "EDGE_FORWARD_URL",
    "SKIP_INFRA_DOWNLOADS",
    "STEPFUNCTIONS_LAMBDA_ENDPOINT",
    "WINDOWS_DOCKER_MOUNT_PREFIX",
    "HOSTNAME_FROM_LAMBDA",
    "LOG_LICENSE_ISSUES",
    "SYNCHRONOUS_API_GATEWAY_EVENTS",
    "SYNCHRONOUS_KINESIS_EVENTS",