Downgrade to ExoPlayer 2.11.8

[Redirion]

What is it?

• Bugfix (user facing)
• Feature (user facing)
• Codebase improvement (dev facing)
• Meta improvement to the project (dev facing)

Description of the changes in your PR

Well here we go again. Yet another ExoPlayer downgrade to see if that helps with the buffering issues.
I included by accident the changes from #6515, but that shouldn't hurt.

Fixes the following issue(s)

• Fixes Buffering video unrelated to connection #6510 (hopefully)

APK testing

On the website the APK can be found by going to the "Checks" tab below the title and then on "artifacts" on the right.

Due diligence

• I read the contribution guidelines.

[opusforlife2]

Holy poop. I think this is it!

I didn't realise this before, but (probably) since the update to 2.12, the player didn't buffer ahead that much (the bright red line wasn't visible or was very short).

With 2.11, the difference is clearly visible. The player buffers ahead by a LOT (the bright red line looks like it's buffered ahead at least a minute or more).

At least this is how the UI behaves. Whether that clearly loaded buffer is a placebo or there is actually a difference in buffering, I don't know.

[TacoTheDank]

Reject modernity, return to old versions... 😭

[CBSkarmory]

This seems to have fixed the issue for me

[TobiGr]

@Redirion Please target the master branch, allowing us to make another hotifx version

[Redirion]

done in #6542

[opusforlife2]

Isn't there a button to switch branches in the same PR? I'm pretty sure I've seen something like that being used earlier.

[plusterkopp]

Is there any build available for download?

[Redirion]

Checks -> Artifacts
But I would not recommend it. This PR does not improve anything