Allow `port`, `protocol` and `fallback` properties in `LoggingConfig`

[kawmra]

Hello,

For local developing, I’m creating a mock server for the Cloud Logging API. To use the mock server, I need to specify a custom API endpoint, port, protocol and enable REST fallback.

It appears the Logging class constructor doesn't expose options for this. However, the underlying clients it uses (like LoggingServiceV2Client) are initialized with google-gax's ClientOptions, which supports apiEndpoint, port, protocol, and fallback.

Could you please consider exposing these properties in LoggingConfig? This would make it much easier to mock the service for local development and testing.

Thanks you.