[FR] Sleep Timer: wait until last song is over

[TechD123]

Is your feature request related to a problem? Please describe.
While setting an arbitrary number of minutes and stopping mid-playback is helpful in some scenarios, I like to have the last song play until it is done (and don't want to do the math in my head to calculate how many minutes I'd need to enter to play the next x songs in queue so that the last song has time to finish).

Describe the solution you'd like
A checkbox in the sleep timer dialog "Wait for current song to end", the question would be if we want this to be ticked by default.

Describe alternatives you've considered
There could also be the option to long press on the sleep timer icon to automatically stop playback after the current song.