### 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_
request.headers[
                "X-Amzn-Trace-Id"
            ] = "Root=1-3152b799-8954dae64eda91bc9a23a7e8;Parent=7fa8c0f79203be72;Sampled=1"
        try:
            aws_client.sns.meta.events.register("before-send.sns.", add_xray_header)
            topic = sns_create_topic()
            topic_arn = topic["TopicArn"]
            queue_url = sqs_create_queue()
            sns_create_s(topic_arn=topic_arn, queue_url=queue_url)
            aws_client.sns.publish(TargetArn=topic_arn, Message="X-Ray propagation test msg")
            response = aws_client.sqs.receive_message(
                QueueUrl=queue_url,
                AttributeNames=["SentTimestamp", "AWSTraceHeader"],
                MaxNumberOfMessages=1,
                MessageAttributeNames=["All"],
                VisibilityTimeout=2,
                WaitTimeSeconds=2,
            )
            assert len(response["Messages"]) == 1
            message = response["Messages"][0]
            snapshot.match("xray-msg", message)
            assert (
                message["Attributes"]["AWSTraceHeader"]
                == "Root=1-3152b799-8954dae64eda91bc9a23a7e8;Parent=7fa8c0f79203be72;Sampled=1"
            )
        finally:
            aws_client.sns.meta.events.unregister("before-send.sns.", add_xray_header)
    @pytest.mark.aws_validated
    def test_create_topic_after_delete_with_new_tags(self, sns_create_topic, snapshot, aws_client):