### 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.add_transformer(
            snapshot.transform.key_value(
                "MD5OfMessageAttributes",
                value_replacement="<md5-hash>",
                reference_replacement=False,
            )
        )
        topic_name = f"topic-{short_uid()}.fifo"
        queue_name = f"queue-{short_uid()}.fifo"
        dlq_name = f"dlq-{short_uid()}.fifo"
        topic_arn = sns_create_topic(
            Name=topic_name,
            Attributes={"FifoTopic": "true"},
        )["TopicArn"]
        response = aws_client.sns.get_topic_attributes(TopicArn=topic_arn)
        snapshot.match("topic-attrs", response)
        queue_url = sqs_create_queue(
            QueueName=queue_name,
            Attributes={"FifoQueue": "true"},
        )
        subscription = sns_create_s(topic_arn=topic_arn, queue_url=queue_url)
        subscription_arn = subscription["SubscriptionArn"]
        if raw_message_delivery:
            aws_client.sns.set_subscription_attributes(
                SubscriptionArn=subscription_arn,
                AttributeName="RawMessageDelivery",
                AttributeValue="true",
            )
        dlq_url = sqs_create_queue(
            QueueName=dlq_name,