Create a verify flag to support verification for entering repair mode

Add a flag provided to verifyCredential API to support verification
for entering repair mode. If the flag is set, the API writes the
password data to the repair mode file after the user credential is
verified successfully. The file is deleted once the device boots
into normal mode.

Bug: 277561275
Test: atest com.android.server.locksettings
Test: adb shell dumpsys lock_settings
Test: am start -a android.app.action.PREPARE_REPAIR_MODE_DEVICE_CREDENTIAL
      The file is created in /metadata/repair-mode after the credential is
      verified.
Change-Id: I8e22c1c9045c1c67de72fae6e9ed581bb4f04b96
Merged-In: I8e22c1c9045c1c67de72fae6e9ed581bb4f04b96
(cherry picked from commit e7a3e9fa)