[Feature Request]: Always have a quick bookmark playlist set if possible

[kommunarr]

Guidelines

• I have searched the issue tracker for open and closed issues that are similar to the feature request I want to file, without success.
• I have searched the documentation for information that matches the description of the feature request I want to file, without success.
• This issue contains only one feature request.

Problem Description

I've seen multiple reports of users not having any playlist set as their Quick Bookmark target, which leads to what most users would consider a substantially lackluster UX for adding videos to playlists.

Assuming it's not due to a bug in our logic that sets the default playlist to Favorites upon first startup of post- custom User Playlists FreeTube, here are the main reasons for why I think users are not seeing any quick bookmark target:

• User clicks "Disable Quick Bookmark" icon without understanding what it means (it kind of looks like a link, maybe? We're leaning heavily on the icon alone to express a pretty complicated and specific meaning. That aspect would be ameliorated by Add icon button visual labels #4950, but I still don't think it's impossible to accidentally click even a well-labeled button at some point and be none the wiser.)
• User deletes their Favorites playlist at some point and uses a different one, not realizing that the Quick Bookmark will disappear until a new playlist is set as that one

Proposed Solution

• Remove ability to "Remove quick bookmark"; only allow to switch it from another playlist where it's not set (icon shows as disabled on playlist where it's set).
• Have "Quick Bookmark" switch to another one automatically (if one exists) upon deletion (or insertion, if the # of playlists was zero), which every FreeTube developer compared to the primary mechanism in the 1994 Christmas film "The Santa Clause" when this topic was first discussed (please don't fact-check this claim).
  • Which one? The one at the top of the selected sort order sounds fine to me.
• Update Quick Bookmark icon enabled/disabled states to match the Quick Bookmark Icon Add to ${playlistName} added/not-added states

Alternatives Considered

Lots of choices are possible here. I don't think there are any other better ones. Removing the ability to have no bookmarked playlist while you do have >0 playlists is one of those things that an extreme minority of users would somewhat mind, but it's greatly outweighed by the amount of users inconvenienced by us allowing that possibility.

Issue Labels

ease of use improvement, improvement to existing feature

Additional Information

No response