desktop: Prefer non-sRGB surface formats

[torokati44]

This is a half measure to unblock #20898 (following emilk/egui#7311) - the colors are probably still not right if only sRGB formats are supported.

[torokati44]

If you have any ideas/capacity, @Dinnerbone, I'd appreciate you helping out (or even taking over, as you please).

[torokati44]

I am now on the opinion that this hasn't even worked correctly before with both sRGB and linear surface formats - the difference is just less noticeable when the mismatch is one way than when in the other (when it's darkening vs. when it's lightening).

[torokati44]

See, wrt. #21730:

egui version / surface format	sRGB	linear
current
updated

(Please excuse the window shadow in one of the screenshots...)
(The text may look different because of emilk/egui#7431?)

[torokati44]

So maybe this should be included in #21730 instead of being separate...?

[torokati44]

actually, since this has nothing to do with wgpu 26, we could switch to the egui 0.32.3 release first, and have this fix included for it, (and then later, if we want wgpu 26, switch back to a later egui master, but that's an independent story).

[torokati44]

Okay, added an egui bump to just after emilk/egui#7311 (but before their wgpu 26 update or the text kerning change) in here, so there shouldn't be a gamma-mismatched, regressed, intermediate state.