### 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_
self, sns_create_platform_application, aws_client
    ):
        response = sns_create_platform_application(
            Name=f"test-{short_uid()}",
            Platform="GCM",
            Attributes={"PlatformCredential": "123"},
        )
        kwargs_list = [
            {"Token": "test1", "CustomUserData": "test-data"},
            {"Token": "test1", "CustomUserData": "test-data"},
            {"Token": "test1"},
            {"Token": "test1"},
        ]
        platform_arn = response["PlatformApplicationArn"]
        responses = []
        for kwargs in kwargs_list:
            responses.append(
                aws_client.sns.create_platform_endpoint(
                    PlatformApplicationArn=platform_arn, **kwargs
                )
            )
        # A
        for i in range(len(responses)):
            assert "EndpointArn" in responses[i]
    @pytest.mark.aws_validated
    def test_publish_by_path_parameters(