[CHORE/ENHANCEMENT] Replace all instances of `coolLerp` with `smoothLerp`

[charlesisfeline]

Linked Issues

closes #5170

Description

the title explains itself. there's like a somewhat large difference, evident by the videos below

also its basically like #3617 but simply just uses smoothLerp instead of a new function i'm not sure if the snapping is intentional but imma just let you guys decide

btw this also gets rid of the deprecated warnings coming from coolLerp specifically

Videos

before:

https://github.com/user-attachments/assets/314380c6-a549-45ef-8853-46bbdfb2f2bb

after:

https://github.com/user-attachments/assets/6a1f6453-8bde-4558-9b9c-3a6ecc16a1f0

[charlesisfeline]

oh yeah side note i was thinking of stripping off the cameraLerp function entirely in addition to coolLerp, but i quickly just decided not to since it would (potentially) break mods that use them

[Starexify]

will also "resolve" a part of my issues #4575 aswell

[charlesisfeline]

superseded by https://github.com/FunkinCrew/Funkin/pull/3617