2025.3.25.1348 - Fix YouTube videos (yt-dlp) & number of fixes & tweaks

Hey everyone! I got a build with a bunch of important bugfixes for you and update to yt-dlp, which should fixup YouTube videos not loading properly.

Major focus is now shifted to Awwdio, but this build fixes a number of things, including OnChanges reflection probes sometimes killing a performance (which turned out to be another Unity bug rabbit-hole).

New Features:

• Implemented asset variant snapshot testing to catch asset variant bugs early (implemented by @probableprime) -- This is mostly an internal change with no user facing bits, but it'll help prevent bugs in asset variant systems from reaching users
• Added "Generate point cloud collider" inspector button to GaussianSplatRenderer -- This will add a point cloud collider made from the gaussian splat centers -- Normally this is generated automatically on import, but in case it's missing, you can use this to generate one on existing splats

Tweaks:

• Updated yt-dlp from 2025.01.26 to 2025.03.25
• Improved SAML implementation to increase its robustness (implemented by @probableprime)

Locale:

• Merged English locale tweak by @_deltawolf
• Merged German locale update by @muppeq
• Merged Japanese locale update by @.aesc
• Merged French locale update by @j4.lc
• Merged Chinese locale update by modimobeikete

Fixes:

• Fixed AmbientLightSH2 not displaying button in the inspector to set it as the source of ambient light in the world (reported by @banane9, @colin.cat, issue #3735, fixed by @bluecyro)
• Fixed cursor size flickering and becoming very large in VR (reported by @dustysprinkles, @gearbell, Mhowser, TisFoolish, @banane9, issue #3654, fixed by @probableprime)
• Fixed GaussianSplatTool not using TipReference for laser (reported by @reddneko, issue #3965)
• Fixed DynamicBoneChain breaking completely when there are invalid bones in the chain (based on report by ko-tengu, issue #3961)
• Fixed OnChanges reflection probes getting stuck and generating endless coroutines, causing significant performance drop (reported by @readun, @firefly2422, @zahndy, issue #3819) -- This was caused due to Unity bug, where disabling a time-sliced reflection probe mid-rendering would result in this probe to be endlessly stuck and never render again