Revert "Revert "[CS] Make NPVC and QuickSettingsController singl..."

Revert submission 23846081-caitlinshk-npvc-singleton-revert

Reason for revert: Root cause b/289133156 has been fixed.

Reverted changes: /q/submissionid:23846081-caitlinshk-npvc-singleton-revert

Change-Id: I30461f8eb1bf3bacd42aef548efaafe071fd268b
14 files changed