Convert all `.less` styles in fixtures to Vanilla Extract styles, update tests, remove redundant fixture and tests

[askoufis]

This is pre-work to removing support for .less styles in sku v13. To prevent a huge PR, I've split up feature removal (will be in a follow up PR) from the style conversion/test updates (this PR).

The changes should be fairly straightforward. Basically just converted all less styles in fixtures to VE styles, and updated tests accordingly. The react-css-modules fixture was doing a subset of the tests that the typescript-css-modules fixture already does, so I removed the entire fixture.

There's potentially some more redundant tests/fixtures we could clean up, and we should ideally rename typescript-css-modules to something like typescript-vanilla-extract, but I didn't want to bloat the PR too much, so I'll probably get to that stuff post-v13 release.

[changeset-bot[bot]]

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Latest commit: 102bb7983073a0b0b5eba2088f53810361befa12

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