Modify PK Settings page to make it more user friendly

PK Settings page:
    - Show current PK layout selected for the current user profile and current IME language instead of a list of IMEs

PK layout mapping page:
    - Show IME name in header only if multiple active IMEs
    - Show the PK layout selection criteria (Automatic v/s User selected)

Bug: 325925410
Bug: 326195401
Test: manual
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:8754f114ac48cb80c367c11769947553f5c56034)
Merged-In: I93a2e169742a800fa116fa5d55e1a91e5548cebb
Change-Id: I93a2e169742a800fa116fa5d55e1a91e5548cebb