### 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_
inv_result = lambda_client.invoke(
                FunctionName=subscriber["Endpoint"],
                Payload=to_bytes(event),
                InvocationType=InvocationType.Event,
            )
            status_code = inv_result.get("StatusCode")
            payload = inv_result.get("Payload")
            if payload:
                delivery = {
                    "statusCode": status_code,
                    "providerResponse": json.dumps(
                        {"lambdaRequestId": inv_result["ResponseMetadata"]["RequestId"]}
                    ),
                }
                store_delivery_log(context.message, subscriber, success=True, delivery=delivery)
        except Exception as exc:
            LOG.info(
                "Unable to run Lambda function on SNS message: %s %s", exc, traceback.format_exc()
            )
            store_delivery_log(context.message, subscriber, success=False)
            message_body = create_sns_message_body(
                message_context=context.message, subscriber=subscriber
            )
            sns_error_to_dead_letter_queue(subscriber, message_body, str(exc))
    def prepare_message(self, message_context: SnsMessage, subscriber: SnsSubscription) -> str:
        """
        You can see Lambda SNS Event format here: https://docs.aws.amazon.com/lambda/latest/dg/with-sns.html
        :param message_context: the SnsMessage containing the message data
        :param subscriber: the SNS subscription
        :return: an SNS message body formatted as a lambda Event in a JSON string