### Is there an existing issue for this?

- [X] I have searched the existing issues

### Feature description

SNS allows for the publishing of messages to an SMS destination with a phone number. Those messages are logged and stored in the `SnsStore`, but there is no way to retrieve them for verification. The request here is to expose a new endpoint which returns SMS messages from the store, similar to the one made available to retrieve email messages sent via SES.

### 🧑‍💻 Implementation

The `SNSServicePlatformEndpointMessagesApiResource` class makes endpoints available for accessing platform endpoint messages sent via SNS. A similar resource class could be implemented to provide new endpoints for accessing SMS messages.

Given that interaction platform endpoint messages is exposed at the path `/_aws/sns/platform-endpoint-messages`, SMS message interaction would presumably be exposed at `/_aws/sns/sms-messages`. A `GET` endpoint could accept an optional `phoneNumber` query parameter to filter messages based on the destination phone number.

```python
class SNSServiceSMSMessagesApiResource:
  @route(sns_constants.SMS_MSGS_ENDPOINT, methods=["GET"])
    def on_get(self, request: Request):
      account_id = #...
      region = #...
      filter_phone_number = request.args.get("phoneNumber")
      # get store; conditionally filter messages based on filter_phone_number
```

### Anything else?

_No response_
)
from localstack.utils.aws.arns import ArnData, parse_arn
from localstack.utils.strings import short_uid
LOG = logging.getLogger(__name__)
class SnsProvider(SnsApi, ServiceLifecycleHook):
    """
    Provider class for AWS Simple Notification Service.
    AWS supports following operations in a cross-account setup:
    - GetTopicAttributes
    - SetTopicAttributes
    - AddPermission
    - RemovePermission
    - Publish
    - Subscribe
    - ListSubscriptionByTopic
    - DeleteTopic
    """
    def __init__(self) -> None:
        super().__init__()
        self._publisher = PublishDispatcher()
    def on_before_stop(self):
        self._publisher.shutdown()
    def on_after_init(self):
        
        register_sns_api_resource(ROUTER)
    @staticmethod
    def get_store(account_id: str, region_name: str) -> SnsStore:
        return sns_stores[account_id][region_name]
    @staticmethod
    def get_moto_backend(account_id: str, region_name: str) -> SNSBackend: