### 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.jsonpath(
                "$..Messages..MessageAttributes.RequestID.Value", "request-id"
            )
        )
        # c
        dlq_topic_arn = sns_create_topic()["TopicArn"]
        queue_url = sqs_create_queue()
        # s
        sns_create_s(topic_arn=dlq_topic_arn, queue_url=queue_url)
        # c
        lambda_topic_arn = sns_create_topic()["TopicArn"]
        function_name = f"lambda-function-{short_uid()}"
        lambda_creation_response = create_lambda_function(
            func_name=function_name,
            handler_file=TEST_LAMBDA_PYTHON,
            runtime=Runtime.python3_9,
            role=lambda_su_role,
            DeadLetterConfig={"TargetArn": dlq_topic_arn},
        )
        snapshot.match(
            "lambda-response-dlq-config",
            lambda_creation_response["CreateFunctionResponse"]["DeadLetterConfig"],
        )
        lambda_arn = lambda_creation_response["CreateFunctionResponse"]["FunctionArn"]
        # a
        permission_id = f"test-statement-{short_uid()}"
        aws_client.awslambda.add_permission(
            FunctionName=function_name,