make BreadCrumbs UPO appear in Special:Preferences#mw-prefsection-rendering

fixes the problem
https://www.mediawiki.org/wiki/Extension_talk:BreadCrumbs#Make_Bread_Crumb_UPO_appear_in_Special:Preferences.23mw-prefsection-rendering_25512

Bug: 57757
Change-Id: I331b1f7d96e044125527be623b37c69dfd80d052