Administration: Ensure visual consistency with large titles in the sidebar.

Custom posts, and other menu titles that are long aren't wrapping correctly.

Props jagirbaheshwp, munyagu, harshbarach, hareesh-pillai, pratikkry, naveenkharwar, mukesh27, dushanthi, worldweb, audrasjb, afercia, amolv, iqbalbary, davidbaumwald.
Fixes #42201

Built from https://develop.svn.wordpress.org/trunk@46453


git-svn-id: https://core.svn.wordpress.org/trunk@46251 1a063a9b-81f0-0310-95a4-ce76da25c4cd