Miscellaneous Bugfixes From My Multiplayer Branch

This is just a bunch of bugfixes I did while I was working on the Multiplayer Support PR. I know I should've kept them separate, but then I'd also be dealing with said bugs. So this PR adds most of the bugfixes I did while working on Multiplayer.

- De-globalized Pipe SFX from Pipe Cutscene (helps with lowering audio)
- De-globalized 1-up SFX for Players
- Removed an error log spam with the `ResourceSetter`s (involving connecting already connected signals)
- Made sure to insert "BaseAssets" folder into the FIRST slot in the Resource Packs array.
- Replaced `"BaseAssets"` for the above fix with `Godot.ROM_PACK_NAME`
- Removed unused `"character"` setting from `SettingsManager`
- Reset P-Switch timer when `Global.reset_values()` is called. Fixes bug when pressing a P-Switch and immediately restarting the level.
- Added Skid SFX to `AudioManager`
- Added slightly longer delay for when pausing with a controller (it can easily unpause before you press the button again)
- Null check if LevelBG is in the level or not (for added for test levels)

Scripts/Classes/Singletons/AudioManager.gd

@@ -5,6 +5,7 @@ const DEFAULT_SFX_LIBRARY := {
 	"big_jump": ("res://Assets/Audio/SFX/BigJump.wav"),
 	"coin": ("res://Assets/Audio/SFX/Coin.wav"),
 	"bump": ("res://Assets/Audio/SFX/Bump.wav"),
+	"skid": ("res://Assets/Audio/SFX/Skid.wav"),
 	"pipe": ("res://Assets/Audio/SFX/Pipe.wav"),
 	"damage": ("res://Assets/Audio/SFX/Damage.wav"),
 	"power_up": ("res://Assets/Audio/SFX/Powerup.wav"),