Admin toolbar: remove unneeded overrides of `z-index` and `left` on screens narrower than 782px. Props avryl, babbardel. Fixes #29867.
Built from https://develop.svn.wordpress.org/trunk@30764


git-svn-id: http://core.svn.wordpress.org/trunk@30754 1a063a9b-81f0-0310-95a4-ce76da25c4cd