### 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_
self,
        context: RequestContext,
        topic_arn: topicARN,
        publish_batch_request_entries: PublishBatchRequestEntryList,
    ) -> PublishBatchResponse:
        if len(publish_batch_request_entries) > 10:
            raise TooManyEntriesInBatchRequestException(
                "The batch request contains more entries than permissible."
            )
        parsed_arn = parse_and_validate_topic_arn(topic_arn)
        store = self.get_store(account_id=parsed_arn["account"], region_name=context.region)
        if topic_arn not in store.topic_subscriptions:
            raise NotFoundException(
                "Topic does not exist",
            )
        ids = [entry["Id"] for entry in publish_batch_request_entries]
        if len(set(ids)) != len(publish_batch_request_entries):
            raise BatchEntryIdsNotDistinctException(
                "Two or more batch entries in the request have the same Id."
            )
        response: PublishBatchResponse = {"Successful": [], "Failed": []}