[jazzy] Add test cases for logging service

[Yadunund]

Ref: ros2/demos#611

[marcoag]

Isn't this covered by: https://docs.ros.org/en/jazzy/Tutorials/Demos/Logging-and-logger-configuration.html#logger-level-configuration-externally ? Or do we wanna add something else?

[Yadunund]

I think this ticket was opened before the docs website was updated. So we can close this ticket since a test case for this feature should be generated when scraping the docs sitemap.