### 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_
return EDGE_PORT_HTTP or EDGE_PORT
def get_edge_url(localstack_hostname=None, protocol=None):
    port = get_edge_port_http()
    protocol = protocol or get_protocol()
    localstack_hostname = localstack_hostname or LOCALSTACK_HOSTNAME
    return "%s://%s:%s" % (protocol, localstack_hostname, port)
populate_configs()
if DEBUG:
    logging.getLogger("").setLevel(logging.DEBUG)
    logging.getLogger("localstack").setLevel(logging.DEBUG)
if LS_LOG in TRACE_LOG_LEVELS:
    load_end_time = time.time()
    LOG = logging.getLogger(__name__)
    LOG.debug(
        "Initializing the configuration took %s ms", int((load_end_time - load_start_time) * 1000)
    )
class ServiceProviderConfig(Mapping[str, str]):
    _provider_config: Dict[str, str]
    default_value: str
    def __init__(self, default_value: str):
        self._provider_config = {}
        self.default_value = default_value
    def get_provider(self, service: str) -> str:
        return self._provider_config.get(service, self.default_value)
    def set_provider_if_not_exists(self, service: str, provider: str) -> None:
        if service not in self._provider_config:
            self._provider_config[service] = provider
    def set_provider(self, service: str, provider: str):