[ISSUE] Combat music does not stop if no previous track is playing in the scene

[lucasmiranda2711]

Description:
The Quick Combat module has a feature where a combat soundtrack starts playing when combat begins, and when the combat ends it reverts to the previous track that was playing in the scene.

However, if no previous track is present in the scene, the combat music keeps playing indefinitely after the combat ends.

Expected behavior:
If no previous music is set in the scene, the combat music should stop once combat ends, returning to silence.

Steps to reproduce:
Open a scene with no music configured.
Start a combat.
Select a combat music track.
End the combat.

Actual behavior:
The combat music continues to play indefinitely.