plugins.chzzk: live detail api response validation error fix

[Clap2rap]

Fixes: #6001

Any better suggestions are welcome.

[bastimeyer]

Thanks for the PR. Changes look fine.

However, should there be a need for extending the validation schemas even further, then I'd say that the error handling code should be moved from the Plugin subclass (_get_live() and _get_video()) to the API class. The error handling is currently done in the Plugin subclass, so that it can simply return None instead of having to raise a NoStreamsError in the API class. Irrelevant here though, just a quick thought...

Talking about error handling, are VODs also affected by a potential None return type?

[Clap2rap]

Not affected, based on VODs I've tested. All the VODs have non-null content if they exist. Otherwise, the API returns a code field with the value 404 (or other error codes) and a message field indicating that the VOD does not exist (or other error messages).

And I agree with what you said. Raising NoStreamsError would be a more elegant way to handle it.