Fixes

Related to #4305 by @zackkrida

Description

This PR adds the dark snapshots to the Storybook tests.

It also adds a 100ms wait after taking the light snapshot, before taking the dark mode snapshot, to make sure that the dark theme has fully rendered (otherwise, the white line underneath the filters tabs was saved as anywhere between gray and white, depending on how much of the theme switching was finished by the time of the snapshot).
The "slim-filled-borderless" focus test was removed since we no longer use this class.

Testing Instructions

Look through the added snapshots. Only dark mode storybook snapshots should be added. Some elements might need fixing, but not in scope of this PR. The CI should pass.

Checklist

• My pull request has a descriptive title (not a vague title likeUpdate index.md).
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• I ran the DAG documentation generator (ov just catalog/generate-docs for catalog
  PRs) or the media properties generator (ov just catalog/generate-docs media-props
  for the catalog or ov just api/generate-docs for the API) where applicable.

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