### 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_name = "sample_topic"
        topic_1 = sns_primary_client.create_topic(Name=topic_name)
        topic_1_arn = topic_1["TopicArn"]
        # c
        queue_name = "sample_queue"
        queue_1 = sqs_primary_client.create_queue(QueueName=queue_name)
        queue_1_url = queue_1["QueueUrl"]
        queue_1_arn = sqs_queue_arn(queue_1_url)
        # c
        queue_2 = sqs_secondary_client.create_queue(QueueName=queue_name)
        queue_2_url = queue_2["QueueUrl"]
        # t
        queue_2_arn = sqs_queue_arn(queue_2_url)
        # t
        sns_primary_client.subscribe(
            TopicArn=topic_1_arn,
            Protocol="sqs",
            Endpoint=queue_1_arn,
        )
        # t
        sns_primary_client.subscribe(
            TopicArn=topic_1_arn,
            Protocol="sqs",
            Endpoint=queue_2_arn,
        )
        # n
        # l
        sns_primary_client.publish(TopicArn=topic_1_arn, Message="TestMessageOwner")
        def get_messages_from_queues(message_content: str):