Add a settings key to expose the device's repair mode state

Bug: 277561275
Test: atest SettingsBackupTest
Change-Id: I35dd77bb99ca7e2eecc8439c2c61481c658c5052
Merged-In: I35dd77bb99ca7e2eecc8439c2c61481c658c5052
(cherry picked from commit 5af73f5f26fa7c724826a6d38d9ca0dbf05153f6)
2 files changed