Interior cabin sound update bug fix for 1.43.1

This mod adds the following fixes for ETS2 base game trucks affected by the 1.43.1 interior cabin sound update.

* Balanced sounds: Stopped interior sounds from being louder than when the camera is outside and next to the engine.
* Reduced the excess reverb in the cabin.
* Lowered sound volume of high pitch sounds such as turbo when windows are closed.

It is useful for those preferring a similar sound experience that 1.42 provided.
The Sound Fixes Pack is also providing these fixes, however they will expire on December 14, 2021 for compatibility with future 1.43 sound mods.
The extra few days is to buy time for other sound modders to adapt. Therefore, this mod is intended as an interim fix for default trucks in 1.43.1.

Modders are welcome to use the baseline settings provided in this mod for sound_effects_units.sui
Tip: Do not stray too far in increasing gain values, because it may affect all sounds such as traffic and ambient sounds.

Credits:
Drive Safely