Default Track Settings & Unify VideoPlayerSettingsView

[JPKribs]

Summary

Resolves: #1068

Because of how #1581 configured it, we are already pulling the default track selection based on the UserDto.UserConfiguration settings that we get from the server. This PR just adds a new setting to update these values from Swiftfin instead of relying on folks changing this from Jellyfin-Web:

Settings > Playback > Audio Settings

Settings > Subtitles > Subtitles

This PR also fully refactors VideoPlayerSettingsView to be platform agnostic.

This PR also migrates ServerUserAdminViewModel to stateful and cleans up the views that use this. Most of these are a straight change but some of these there was some additional cleanup. The 3 big cleanups were reducing the comments that I originally put in there, combining vars when they were needlessly split up (by me), and finally, removing duplicate deletion logic.

TODO

• Localize strings
• Wait on some other PRs that touch these views to avoid merging conflicts

Videos

Swiftfin to Web Sync

Screen.Recording.2026-03-01.at.12.31.53.mov

tvOS

Simulator.Screen.Recording.-.Apple.TV.-.2026-02-27.at.17.18.25.mov

iOS

Simulator.Screen.Recording.-.iPhone.-.2026-02-27.at.17.22.16.mov

[JPKribs]

This PR is done but there is a lot of localizing. I also touch this same place via other outstanding PRs. When those are closed, I will finish up the localization and finalize this one. Videos are up-to-daet!