Add a settings key to expose the device's repair mode state am: 0e1d0ecf am:...

Add a settings key to expose the device's repair mode state am: 0e1d0ecf am: 14cb34fa am: 564f1e04

Original change: https://android-review.googlesource.com/c/platform/frameworks/base/+/2781891



Change-Id: I8f8a2329a65e0366004dc0681c701e8d0657d12b
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>