Revert "Create rainbow_cube.svg"

[jfly]

Reverts #212

@VictorMdN, FYI, your change caused some tests to fail: https://github.com/cubing/icons/actions/runs/23811841789.

We recently made our tests stricter, so this isn't a surprise. Could you send in a new PR with the tests passing?

[VictorMdN]

Some errors are easy to fix, but the test no longet support masks. I need this for the code to pass the tests.

[jfly]

Which test is preventing masks? Why do you need them? I'm ok allowing them, just curious.

[VictorMdN]

Expected to be one of: [ "svg", "g", "path", "circle", "defs" ] Received: "mask" at checkElement (/home/runner/work/icons/icons/script/test-svg.spec.ts:126:60)

Received: "white" at checkElement (/home/runner/work/icons/icons/script/test-svg.spec.ts:76:69) at checkElement (/home/runner/work/icons/icons/script/test-svg.spec.ts:91:9)

These two.

I used a mask to simplify the definition. Didn't need to draw the stickers, just the cuts. This way, I didn't have to calculate size or position of the stickers (given the size of the cuts) and I could focus on making it mathematically accurate.

[jfly]

@VictorMdN, that sounds totally reasonable to me. Could you send in another PR that relaxes those tests and adds your icon?

[lgarron]

Unfortunately, ImageMagick does not handle the <mask> element properly — at least not ImageMagick 7.1.2-21 on my macOS 26.4.1 system. Since ImageMagick is the de facto open-source choice for image processing, this means that it will break a whole bunch of use cases.

This is what the output of magick https://raw.githubusercontent.com/cubing/icons/c75eed3fe7a2b384b2e550bd139ddb24424580eb/src/svg/unofficial/rainbow_cube.svg rainbow_cube.svg.png looks like on my computer:

I would prefer to avoid <mask> unless we know how to make it compatible across a wide range of use cases.