Fixup ModifierShortcutManager#getApplicatioNShortcuts on HSUM

A bug has crept back in where we end up using an incorrect user context
in modifier shortcut manager and so some shortcuts aren't resolving when
we pass back to the shortcut helper.

Bug: 370739671
Flag: EXEMPT trivial bug fix.
Test: Manually verify in shortcut helper.
Change-Id: I50da4539929446b2c400d3ccdaef6f6a107e82e7