Improve CSS output in tests to better reflect reality

[RobinMalfait]

This PR improves the expected CSS output in our tests. We are now using lightning css which produces
a more optimized CSS output.

Right now the tests are setup in a way that both the generated css and expected css are run through lightningcss to make sure that the output is concistent for the stable and oxide engines. But this also means that the expected output could be larger (aka not optimized) and still matches (after it runs through lightningcss).

By replacing this with the more optimal output we achieve a few things:

1. This better reflects reality since we will be using lightningcss.
2. This gets rid of unnecessary css.
3. Removed code!

Lightning CSS makes use of the browserslist, currently for our tests we told it to use Chrome v106. This is also the reason why certain things are squashed now:

Before:

*,
::before,
::after {
  --tw-border-spacing-x: 0;
  --tw-border-spacing-y: 0;
  --tw-translate-x: 0;
  --tw-translate-y: 0;
  --tw-rotate: 0;
  --tw-skew-x: 0;
  --tw-skew-y: 0;
  --tw-scale-x: 1;
  --tw-scale-y: 1;
  --tw-pan-x: ;
  --tw-pan-y: ;
  --tw-pinch-zoom: ;
  --tw-scroll-snap-strictness: proximity;
  --tw-ordinal: ;
  --tw-slashed-zero: ;
  --tw-numeric-figure: ;
  --tw-numeric-spacing: ;
  --tw-numeric-fraction: ;
  --tw-ring-inset: ;
  --tw-ring-offset-width: 0px;
  --tw-ring-offset-color: #fff;
  --tw-ring-color: ${defaultRingColor};
  --tw-ring-offset-shadow: 0 0 #0000;
  --tw-ring-shadow: 0 0 #0000;
  --tw-shadow: 0 0 #0000;
  --tw-shadow-colored: 0 0 #0000;
  --tw-blur: ;
  --tw-brightness: ;
  --tw-contrast: ;
  --tw-grayscale: ;
  --tw-hue-rotate: ;
  --tw-invert: ;
  --tw-saturate: ;
  --tw-sepia: ;
  --tw-drop-shadow: ;
  --tw-backdrop-blur: ;
  --tw-backdrop-brightness: ;
  --tw-backdrop-contrast: ;
  --tw-backdrop-grayscale: ;
  --tw-backdrop-hue-rotate: ;
  --tw-backdrop-invert: ;
  --tw-backdrop-opacity: ;
  --tw-backdrop-saturate: ;
  --tw-backdrop-sepia: ;
}
::backdrop {
  --tw-border-spacing-x: 0;
  --tw-border-spacing-y: 0;
  --tw-translate-x: 0;
  --tw-translate-y: 0;
  --tw-rotate: 0;
  --tw-skew-x: 0;
  --tw-skew-y: 0;
  --tw-scale-x: 1;
  --tw-scale-y: 1;
  --tw-pan-x: ;
  --tw-pan-y: ;
  --tw-pinch-zoom: ;
  --tw-scroll-snap-strictness: proximity;
  --tw-ordinal: ;
  --tw-slashed-zero: ;
  --tw-numeric-figure: ;
  --tw-numeric-spacing: ;
  --tw-numeric-fraction: ;
  --tw-ring-inset: ;
  --tw-ring-offset-width: 0px;
  --tw-ring-offset-color: #fff;
  --tw-ring-color: ${defaultRingColor};
  --tw-ring-offset-shadow: 0 0 #0000;
  --tw-ring-shadow: 0 0 #0000;
  --tw-shadow: 0 0 #0000;
  --tw-shadow-colored: 0 0 #0000;
  --tw-blur: ;
  --tw-brightness: ;
  --tw-contrast: ;
  --tw-grayscale: ;
  --tw-hue-rotate: ;
  --tw-invert: ;
  --tw-saturate: ;
  --tw-sepia: ;
  --tw-drop-shadow: ;
  --tw-backdrop-blur: ;
  --tw-backdrop-brightness: ;
  --tw-backdrop-contrast: ;
  --tw-backdrop-grayscale: ;
  --tw-backdrop-hue-rotate: ;
  --tw-backdrop-invert: ;
  --tw-backdrop-opacity: ;
  --tw-backdrop-saturate: ;
  --tw-backdrop-sepia: ;
}

After:

*,
:before,
:after,
::backdrop {
  --tw-border-spacing-x: 0;
  --tw-border-spacing-y: 0;
  --tw-translate-x: 0;
  --tw-translate-y: 0;
  --tw-rotate: 0;
  --tw-skew-x: 0;
  --tw-skew-y: 0;
  --tw-scale-x: 1;
  --tw-scale-y: 1;
  --tw-pan-x: ;
  --tw-pan-y: ;
  --tw-pinch-zoom: ;
  --tw-scroll-snap-strictness: proximity;
  --tw-ordinal: ;
  --tw-slashed-zero: ;
  --tw-numeric-figure: ;
  --tw-numeric-spacing: ;
  --tw-numeric-fraction: ;
  --tw-ring-inset: ;
  --tw-ring-offset-width: 0px;
  --tw-ring-offset-color: #fff;
  --tw-ring-color: ${defaultRingColor};
  --tw-ring-offset-shadow: 0 0 #0000;
  --tw-ring-shadow: 0 0 #0000;
  --tw-shadow: 0 0 #0000;
  --tw-shadow-colored: 0 0 #0000;
  --tw-blur: ;
  --tw-brightness: ;
  --tw-contrast: ;
  --tw-grayscale: ;
  --tw-hue-rotate: ;
  --tw-invert: ;
  --tw-saturate: ;
  --tw-sepia: ;
  --tw-drop-shadow: ;
  --tw-backdrop-blur: ;
  --tw-backdrop-brightness: ;
  --tw-backdrop-contrast: ;
  --tw-backdrop-grayscale: ;
  --tw-backdrop-hue-rotate: ;
  --tw-backdrop-invert: ;
  --tw-backdrop-opacity: ;
  --tw-backdrop-saturate: ;
  --tw-backdrop-sepia: ;
}

Also important to note that this PR doesn't touch actual implementation. Just test output, that way we can know for sure that we didn't break anything because we didn't update code + tests 👍