### 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_
"""Returns True if host responds to a ping request"""
    is_windows = platform.system().lower() == "windows"
    ping_opts = "-n 1" if is_windows else "-c 1"
    args = "ping %s %s" % (ping_opts, host)
    return (
        subprocess.call(args, shell=not is_windows, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
        == 0
    )
def in_docker():
    """
    Returns True if running in a docker container, else False
    Ref. https://docs.docker.com/config/containers/runmetrics/#control-groups
    """
    if OVERRIDE_IN_DOCKER:
        return True
    
    if os.path.exists("/.dockerenv"):
        return True
    if os.path.exists("/run/.containerenv"):
        return True
    if not os.path.exists("/proc/1/cgroup"):
        return False
    try:
        if any(
            [
                os.path.exists("/sys/fs/cgroup/memory/docker/"),
                any(
                    "docker-" in file_names
                    for file_names in os.listdir("/sys/fs/cgroup/memory/system.slice")