Duplication Bug in Playlists with duplicate tracks

This bug appears to be related to restoring/undoing a playlist edit when more than 1 copy of a track is on the playlist. This was tested with MP3 files stored locally on the device.

Reproduction:

1. Create a playlist with a audio file.
2. Add the audio file to the playlist again, there will be 2 entries.
3. Go to the playlist, swipe one of the tracks away. You will receive a popup entry allowing you to 'Cancel' the action.
4. Press the cancel button.
5. The playlist will now have 3 tracks instead of 2. You may have to exit the playlist and reopen it to see the new tracks.

Testing notes:

• This bug appears to duplicate the existing entries that were remaining after the remove action. Example: If there are 4 copies, removing 1 and cancelling will result in 7 tracks.
• If there is only 1 copy of a track in the playlist, it does not duplicate.
• If other tracks are present and have duplicates, they are not affected. This only affects the duplicates of the removed track.

OS: Android 11 RP1A.201105.002 VLC Version: 3.3.1 Revision 3470199f VLC: 28eddab6 (2020-10-06) Hardware: Pixel 4a

If someone points me to the source for the android version, I can take a look at what might be causing it. I don't have the skills to patch it, but I might be able to save some effort for those who do.