Add padding (not margin) to the privilege filter menu

Currently, the menu looks like this

Please add space (padding) so the selectable element for adding filters is evenly centered in the menu. Don't center the text, just the object.

The issue names no file, test, or entry point. Locate the privilege filter menu and inspect its existing layout styles; the work is done when padding, rather than margin, evenly centers the selectable filter element without centering its text.

Written by the indexing model from the issue text.