Cherrypick 2 changes for today's LD

Make sure KeepGoingDrawer gets set correctly

Seems the exception is caught inside mw.loader.using so wasn't
surfacing

ChangeId: I7ca9d27ed7fb24cd08e4ef43da68595f87d4d21f

Hide drawers underneath overlays

Don't close them as they might still be relevant (for example on
keep going campaign you might change your mind about editing the
current page)

ChangeId: I8f283b44a1cef97e6935bf2eb246a882a243f6b7

Change-Id: I0060fac08f0e57348d9565bb559b922c99388f18