Adjust fullscreen fit mode based on aspect ratio of current video

[TippyLion28]

Checklist

• I checked, but didn't find any duplicates (open OR closed) of this issue in the repo.
• I have read the contribution guidelines given at https://github.com/TeamNewPipe/NewPipe/blob/HEAD/.github/CONTRIBUTING.md.
• This issue contains only one feature request. I will open one issue for every feature I want to request.

What feature do you want?

See title. Some creators post content in a slightly wider format. While not quite matching the taller aspect of my phone's display, it comes a lots closer than the 16:9 aspect ratio of most of the content on YouTube.

In these scenarios, I prefer watching the video in Zoom mode as it completely fills my display without sacrificing too much of the content. Most of these wide aspect videos are in 4K, so I'm also not sacrificing too much video quality by being slightly zoomed in.

However, in the absence of pinch-to-zoom which is covered by other issues, it would be nice to have an option to automatically change the fit mode depending on the aspect ratio of the currently playing video.

Why do you want this feature?

Saves me having to change the fit mode every time I watch an LTT or MKBHD video :)

[busssard]

I support this issue, albeit from exactly the opposite side.

When in fullscreen the player cuts away some content at top and bottom, due to the very long screen of my phone.
I rather have a black bar on either side than miss some of the video. So being able to select how to fit the video in fullscreen would be amazing!