Administration: Widen screen options number of items field.

Modifies the Screen Options > Number of items per page field to avoid cropping of three digit numbers when setting a list view to display a lot of items.

Props apermo, audrasjb, darshitrajyaguru97, ekla, gaurangsondagar, jigarkahar, juanmaguitar, khushdoms, peterwilsoncc, sabernhardt, shailu25, shatrumyatra, yusufmudagal.
Fixes #65104.



git-svn-id: https://develop.svn.wordpress.org/trunk@62268 602fd350-edb4-49c9-b593-d223f7449a82