### 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, sns_create_topic, sqs_create_queue, sns_create_s, snapshot, aws_client
    ):
        topic_arn = sns_create_topic()["TopicArn"]
        queue_url = sqs_create_queue()
        rs = aws_client.sns.publish(
            TopicArn=topic_arn, Subject="test-subject-before-sub", Message="test_message_before"
        )
        snapshot.match("publish-before-subscribing", rs)
        sns_create_s(topic_arn=topic_arn, queue_url=queue_url)
        message_subject = "test-subject-after-sub"
        message_body = "test_message_after"
        rs = aws_client.sns.publish(
            TopicArn=topic_arn, Subject=message_subject, Message=message_body
        )
        snapshot.match("publish-after-subscribing", rs)
        response = aws_client.sqs.receive_message(
            QueueUrl=queue_url, VisibilityTimeout=0, WaitTimeSeconds=5
        )
        # n
        snapshot.match("receive-messages", response)
    @pytest.mark.aws_validated
    def test_create_duplicate_topic_with_more_tags(self, sns_create_topic, snapshot, aws_client):