### 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_
# c
        # o
        topic_arn = sns_create_topic()["TopicArn"]
        # a
        fake_arn = f"{topic_arn}-fake"
        message = "This is a test message"
        # t
        response = aws_client.sns.publish(TopicArn=topic_arn, Message=message)
        snapshot.match("success", response)
        # t
        with pytest.raises(ClientError) as e:
            aws_client.sns.publish(TopicArn=fake_arn, Message=message)
        snapshot.match("error", e.value.response)
    @pytest.mark.only_localstack
    def test_publish_sms(self, aws_client):
        response = aws_client.sns.publish(PhoneNumber="+33000000000", Message="This is a SMS")
        assert "MessageId" in response
        assert response["ResponseMetadata"]["HTTPStatusCode"] == 200
    @pytest.mark.aws_validated
    def test_publish_non_existent_target(self, sns_create_topic, snapshot, aws_client):
        topic_arn = sns_create_topic()["TopicArn"]
        account_id = parse_arn(topic_arn)["account"]
        with pytest.raises(ClientError) as ex:
            aws_client.sns.publish(
                TargetArn=f"arn:aws:sns:us-east-1:{account_id}:endpoint/APNS/abcdef/0f7d5971-aa8b-4bd5-b585-0826e9f93a66",
                Message="This is a push notification",
            )
        snapshot.match("non-existent-endpoint", ex.value.response)
    @pytest.mark.aws_validated
    def test_tags(self, sns_create_topic, snapshot, aws_client):