AccessKit Disable Gifs: Apply to animated avatars

[marcustyphoon]

Description

This applies AccessKit Disable Gifs to animated WebP user avatars.

(Needs some more testing and probably cleanup of the mini label code).

Testing steps

[marcustyphoon]

Ah, webp can be used to serve non-animated images. ex: https://www.tumblr.com/ex/722477112068587520.

(okay yeah picking elena's reblog there was just to make the joke)

anyway, I obviously don't even know if the "feature" that this addresses is intended. I am fairly sure that I can feature detect animated webp by reading the binary webp header (it looked very simple) if needed.

[marcustyphoon]

Animated webp avatars were confirmed to be unintended.

[marcustyphoon]

(Although some icons are still animated. I assumed there was an attempt made to un-animate them, and if I recall correctly that was confirmed to me by a staff member, but if this is not an ongoing process and some icons are stuck this way, maybe this should be merged anyway?)