[Feature Request]: Add language completion percentage in the app

[VipelyRS]

Preflight Checklist

• [X] I use the latest version of YouTube Music (Application).
• [X] I have searched the issue tracker for a feature request that matches the one I want to file, without success.

Problem Description

no easy way to check how complete a translation is

Proposed Solution

Next to each of the language names you could add a little percentage counter to indicate completion status

Alternatives Considered

I think this is probably the best way to do it, its simple and straight foward

Additional Information

I know you can just go to the Weblate but i feel its more convenient to have in the app

[ArjixWasTaken]

a good place to have this may be in a re-designed about pop-up

related #1626, #1371

[Alzamer]

I'd like to work on it - can someone assign me?