Enemy: Play Mothsache attack sound effect on player detection

[Brandon-code96]

Enemy: Play Mothsache attack sound effect on player detection

The Mothsache enemy now plays an attack sound effect when entering the attacking state upon detecting the player.

• Added an AudioStreamPlayer node and linked the attack sound stream to the Mothsache component.
• Implemented corresponding setter functions in the GDScript logic to safely handle audio stream assignments.

Resolves #1020

[manuq]

There are a lot of unwanted changes in this pull request. Please start by cleaning up.

For the pull request description, please follow our contributing guidelines.

[github-actions]

Play this branch at https://play.threadbare.game/branches/Brandon-code96/main/.

(This launches the game from the start, not directly at the change(s) in this pull request.)

[manuq]

Sorry, I didn't realize that this was ready for review again. Next time click "Request" or leave us a comment to let us know.

This is not for this pull request, but testing it I realize that the WAV file (from a previous contributor) has a noise in this part, that I think is unwanted:

Please check the comment on using the AudioStreamPlayer2D node and the WAV folder location. The rest looks good, except there are trailing-whitespace errors. Check https://github.com/endlessm/threadbare/actions/runs/34403586388/job/102863419384 and if you want them automatically fixed, you can install pre-commit as explained here https://github.com/endlessm/threadbare/wiki/Contributing#coding-style