[Feature request] Improve VR projection type detection

[syeopite]

Is your enhancement request related to a problem? Please describe.

In order to render a VR video correctly, we need a projection type. Invidious currently attempts to detect this via the projectionType attribute in the adaptiveFormats.

https://github.com/iv-org/invidious/blob/50c8afb525429dcdb5a9b9bb4cf798ee9f62da2a/src/invidious/videos.cr#L764-L767

However, this method isn't ideal:

• EQUIRECTANGULAR always maps to a plain 360 projection
• But MESH can refer to both the EAC projection and it's side-by-side variant: EAC_LR
• Possibly more projection types?

Describe the solution you'd like

Find some full proof method to detect the exact projection type.

Describe alternatives you've considered

Since MESH can either be EAC or EAC_LR we can add a button to let the end-user quickly swap projection types so they can attempt to fix the video themselves.

Additional context

[iBicha]

Reviving this - is EQUIRECTANGULAR still being used? I haven't seen it in a while