### 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_
)
        snapshot.match("messages-no-filter-after-publish-ok", response_after_publish_no_filter)
        aws_client.sqs.delete_message(
            QueueUrl=queue_url_no_filter,
            ReceiptHandle=response_after_publish_no_filter["Messages"][0]["ReceiptHandle"],
        )
        response_after_publish_filter = aws_client.sqs.receive_message(
            QueueUrl=queue_url_with_filter, VisibilityTimeout=0, WaitTimeSeconds=sqs_wait_time
        )
        snapshot.match("messages-with-filter-after-publish-ok", response_after_publish_filter)
        aws_client.sqs.delete_message(
            QueueUrl=queue_url_with_filter,
            ReceiptHandle=response_after_publish_filter["Messages"][0]["ReceiptHandle"],
        )
        # p
        # s
        aws_client.sns.publish_batch(
            TopicArn=topic_arn,
            BatchRequestEntries=[
                {
                    "Id": "1",
                    "Message": "This is another test message",
                    "MessageAttributes": {"attr1": {"DataType": "Number", "StringValue": "111"}},
                }
            ],
        )
        response_after_publish_no_filter = aws_client.sqs.receive_message(
            QueueUrl=queue_url_no_filter, VisibilityTimeout=0, WaitTimeSeconds=sqs_wait_time
        )
        # t