Multiple instances of media player

While playing a song in Media Player, if we send it to the background and then back to the foreground & click on any song, it creates a new instance of MediaPlayer and both the songs are played together.

Reproduce the issue by sending the Media Player to the background, returning it to the foreground, and selecting another song. Start by locating the media-player lifecycle and song-selection entry points; done means selecting a song after resume reuses one player instance and only the intended song plays.

Written by the indexing model from the issue text.