Fix #19555: Users settings: Don't let rows overlap the groups dropdown

[jaller94]

Fixes#19555 by removing the change of z-index on rows.

The line got added in 0428140

[gary-kim]

Hi @jaller94. We met at the Nextcloud conference, nice to see you here!

I think #19533 already includes this change but maybe we can look at getting this in separately. @juliushaertl, what do you think?

[jaller94]

Hi again. 👋
You're right, this is addressed in that PR.
Looks like the other PR may be ready to be merged as well. If #19533 gets merged, feel free to close this.
Otherwise, this may be a minimalist PR to get the unusable select working again.

[gary-kim]

#19533 got merged.
Sorry we couldn't use your PR. Always feel free to continue making contributions!

[rollanders]

This is a big problem. I wish you may solve it soon. Cannot use NC18 as is now.

[gary-kim]

@rollanders#19533 is being backported to stable18 which should fix the issue.