### 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_
message_body = self.prepare_message(context.message, subscriber)
        try:
            region = extract_region_from_arn(subscriber["Endpoint"])
            if role_arn := subscriber.get("SubscriptionRoleArn"):
                factory = connect_to.with_assumed_role(
                    role_arn=role_arn, service_principal=ServicePrincipal.sns, region_name=region
                )
            else:
                factory = connect_to(region_name=region)
            firehose_client = factory.firehose.request_metadata(
                source_arn=subscriber["TopicArn"], service_principal=ServicePrincipal.sns
            )
            endpoint = subscriber["Endpoint"]
            if endpoint:
                delivery_stream = extract_resource_from_arn(endpoint).split("/")[1]
                firehose_client.put_record(
                    DeliveryStreamName=delivery_stream, Record={"Data": to_bytes(message_body)}
                )
                store_delivery_log(context.message, subscriber, success=True)
        except Exception as exc:
            LOG.info(
                "Received error on sending SNS message, putting to DLQ (if configured): %s", exc
            )
            
            
class SmsPhoneNumberPublisher(EndpointPublisher):