Add menu item to mark video as un-watched

[mueller-ma]

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.

Describe the feature you want

Recently PR #6956 added a menu item to mark a video as watched. It doesn't make a lot of sense for videos that are already watched, so IMO the menu item should be changed to "Mark as unwatched" for watched videos.

Is your feature request related to a problem? Please describe it

Not really a problem, I just don't like no-op buttons.

How will you/everyone benefit from this feature?

Currently the "Mark as watched" menu item is a no-op for already watched videos. Replacing it with something more useful or hiding it makes NewPipe better.

[SameenAhnaf]

It doesn't make a lot of sense for videos that are already watched,

It's not useless at least! It has two purposes.

1. Include the video into history. Probably, you watched the video somewhere else from Facebook or native YouTube app.
2. Probably, you needed to watch certain part of the video and you want to use 'Remove fully Watched' function. It's useful in such cases.

so IMO the menu item should be changed to "Mark as unwatched" for watched videos.

You can already delete videos from history. Yes, it's easier to remove the video directly from the feed. I'm not sure if it'll be useful in most other cases.

However, a dedicated 'Watch Later' playlist (suggested in #6880) or notify to watch later at a certain time.

[mueller-ma]

Probably, you watched the video somewhere else from Facebook or native YouTube app.

With "watched" I meant "watched with NewPipe"

you needed to watch certain part of the video and you want to use 'Remove fully Watched' function.

If a video is only watched partly, it isn't fully watched and therefore I wouldn't call it "watched".

[vhouriet]

To my understanding OP doesn't want to remove the feature, just change the "Mark as Watched" to "Mark as Unwatched" or juste remove it completely from the menu for a video that is already completely watched (full red bar). Wich makes sense to me. It would also be useful if you manually marked as watched a video by mistake.