Administration: Remove right padding on form tables on smaller screens so that...

Administration: Remove right padding on form tables on smaller screens so that the spacing is equal on both sides.

Additionally, reduce the right margin on screen meta links (Help and Screen Options) to align with the tables.

Props jainnidhi, garrett-eclipse, ibdz, SergeyBiryukov.
Fixes #43279.
Built from https://develop.svn.wordpress.org/trunk@47622


git-svn-id: https://core.svn.wordpress.org/trunk@47397 1a063a9b-81f0-0310-95a4-ce76da25c4cd