Add SVG pre-commit check to avoid broken colors when using style tags

[ckaiser]

Added a pygrep-based check to pre-commit that checks if any fill, stroke and stop-color properties are being set inside style tags in SVG, this prevents introducing icons that will have broken colors in light modes.

I've ran into this issue twice before in #92504 and #91821, because ImageLoaderSVG does a search & replace on the attribute values but not the style tags, and rather than complicate that code it's probably simpler to just avoid committing SVG it doesn't like in the first place.

[akien-mga]

CC @MewPurPur

[MewPurPur]

IMO we could just reject the style attribute altogether, they are almost always sign of stuff being unoptimized. But this is fine too.

[ckaiser]

Another solution could be running SVGO with the convertStyleToAttrs plugin, and as a bonus we get uniformly optimized svg files.

We're already setting up a node environment for eslint in pre-commit so it wouldn't be that much extra work.

[MewPurPur]

No strong opinion here, I think it's up to Akien to determine if we should run an SVG optimizer constantly. But checking for style attributes which can actually cause bugs seems like a great idea. Currently contributors are supposed to run an optimizer themselves, but sometimes it's not enforced, or it's not immediately clear by reviewers that the file wasn't optimized.

I was going to do another rundown of the repository at some point and see if I can trim a couple kilobytes off of the editor/icons folder by cleaning up the SVGs manually.

[Repiteo]

I've actually played around with an svgo pre-commit hook before, and it indeed works like a charm! It shouldn't be that difficult to setup here; I'll draft up an alternative to showcase how it'll function compared to this implementation

[ckaiser]

Closing in favor of #92766