### 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_
subscriber_arn = subscriber["SubscriptionArn"]
        filter_policy = subscription_filter_policy.get(subscriber_arn)
        if not filter_policy:
            return True
        
        match subscriber.get("FilterPolicyScope", "MessageAttributes"):
            case "MessageAttributes":
                return self.subscription_filter.check_filter_policy_on_message_attributes(
                    filter_policy=filter_policy, message_attributes=message_ctx.message_attributes
                )
            case "MessageBody":
                return self.subscription_filter.check_filter_policy_on_message_body(
                    filter_policy=filter_policy,
                    message_body=message_ctx.message_content(subscriber["Protocol"]),
                )
    def publish_to_topic(self, ctx: SnsPublishContext, topic_arn: str) -> None:
        subscriptions = ctx.store.get_topic_subscriptions(topic_arn)
        for subscriber in subscriptions:
            if self._should_publish(ctx.store.subscription_filter_policy, ctx.message, subscriber):
                notifier = self.topic_notifiers[subscriber["Protocol"]]
                LOG.debug(
                    "Topic '%s' publishing '%s' to subscribed '%s' with protocol '%s' (subscription '%s')",
                    topic_arn,
                    ctx.message.message_id,
                    subscriber.get("Endpoint"),
                    subscriber["Protocol"],
                    subscriber["SubscriptionArn"],
                )
                self.executor.submit(notifier.publish, context=ctx, subscriber=subscriber)
    def publish_batch_to_topic(self, ctx: SnsBatchPublishContext, topic_arn: str) -> None: