### 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_
# d
            sqs_response = aws_client.sqs.receive_message(
                QueueUrl=queue_url,
                WaitTimeSeconds=1,
                VisibilityTimeout=0,
                MessageAttributeNames=["All"],
                AttributeNames=["All"],
            )
            for message in sqs_response["Messages"]:
                messages.append(message)
                aws_client.sqs.delete_message(
                    QueueUrl=queue_url, ReceiptHandle=message["ReceiptHandle"]
                )
            assert len(messages) == 5
        retry(get_messages, retries=10, sleep=0.1)
        # w
        messages.sort(key=itemgetter("Body"))
        snapshot.match("messages", {"Messages": messages})
    @pytest.mark.aws_validated
    def test_publish_batch_messages_without_topic(self, sns_create_topic, snapshot, aws_client):