Fix css override troubles

[akolson]

Summary

This pr fixes unresponsiveness of the trash page Restore button and Add New Folder button in the move resource page caused by the css overriding done when fixing #5322. To fix the issue, a new prop appearanceOverrides has been added to the KTooltip component so its appearance can be better manipulated, particularly the z-index in this case.

Note: Testing this pr is dependent on merging and releasing learningequality/kolibri-design-system#1112

Before:

Restore button

restore.mp4

Add New Folder button

new.folder.mp4

After:
The tooltips still work as before

Screen.Recording.2025-09-03.at.18.38.35.mov

Restore button

Screen.Recording.2025-09-03.at.18.44.29.mov

Add New Folder button

Screen.Recording.2025-09-03.at.18.46.27.mov

Note:
Please note that this a11y contrast issue has been fixed as part of this pr.

References

Fixes #5350
Fixes #5349

Reviewer guidance

• Go to a channel and move or delete a folder or a resource.
• Do one of the following depending on the above;
  • Select the "Open trash" option from the ellipsis button and attempt to restore the deleted folder or resource.
  • For the move option, Click the "Add new folder" to create a folder to move the resource or folder.
• Both operations should work as expected.

[bjester]

There are other tooltips that had the same issues within the modals to begin with, so this only targets a subset-- the recommendation cards. So I feel this PR perpetuates the problematic z-indices and doesn't fully resolve some of the problems either.

The first contributing issue is that the trash and move modals have embedded modals, which is a bad practice to begin with. Moving the those outside helps a little and prepares us better for the Vuetify migration. After solving the former, a solution is to simply have those components toggle between the two modals instead of keeping both open at the same time. Having these modals in the routing could also be a solution, but either way, the solutions handle the modal deficiencies that should be resolved regardless.

[akolson]

@bjester, the latest commit should resolve the issue—thanks for the recommendations. Flattening the embedded modals restored button clickability, but the MessageDialogs were not displaying as expected (due to z-index troubles). To fix this, I migrated the usages of MessageDialog to KModal, which fully resolved the issue.

[bjester]

The nested modals and dialogs are working as expected. The changes seem completely reasonable to me. LGTM! Thanks for handling these regressions @akolson