### 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_
topic_or_target_arn = topic_arn or target_arn
        if is_fifo := (topic_or_target_arn and ".fifo" in topic_or_target_arn):
            if not message_group_id:
                raise InvalidParameterException(
                    "Invalid parameter: The MessageGroupId parameter is required for FIFO topics",
                )
            topic = self._get_topic(topic_or_target_arn, context)
            if topic.content_based_deduplication == "false":
                if not message_deduplication_id:
                    raise InvalidParameterException(
                        "Invalid parameter: The topic should either have ContentBasedDeduplication enabled or MessageDeduplicationId provided explicitly",
                    )
        elif message_deduplication_id:
            
            raise InvalidParameterException(
                "Invalid parameter: MessageDeduplicationId Reason: The request includes MessageDeduplicationId parameter that is not valid for this topic type"
            )
        elif message_group_id:
            raise InvalidParameterException(
                "Invalid parameter: MessageGroupId Reason: The request includes MessageGroupId parameter that is not valid for this topic type"
            )
        is_endpoint_publish = target_arn and ":endpoint/" in target_arn
        if message_structure == "json":
            try:
                message = json.loads(message)
                
                
                
                message = {key: field for key, field in message.items() if isinstance(field, str)}