Playback positions aren't synchronized for stream when foreground and/or background and/or popup player are opened at the same time or switched

[vkay94]

Version

• NewPipe Version 19.6 (official)

Steps to reproduce the bug

1. Open any video in details view (tested with YouTube)
2. Press the buttons for background playback and popup player (+ optionally on the video itself to open the main player)
3. Keep the video playing or seek to any position in popup player/main player

Expected behavior

There are actually two different expections depending on whether the app should allow multiple instances for a single stream or not:

• If the three player types are allowed to be open simultaneously: The current position should be shared/synchronized between all players, so when it is switched (e.g. popup player => main player) the video should resume at the latest position.
• If not allowed: The previous player type should close and the other player should resume at its last position.

Actual behaviour

The current position is not synchronized, so your current progress is not saved when switching the type.

Screenshots/Screen recordings

[wb9688]

Those players are completely separate and this will be solved by #2907