Add a method to write password data

This method will save the current password data to the repair mode
file. This can be used to replace VERIFY_FLAG_WRITE_REPAIR_MODE_PW when
verification is not needed.

Flag: EXEMPT refactor
Bug: 325666121
Test: atest LockscreenRepairModeTest
Test: atest LockPatternUtilsTest
Change-Id: Ibdf9b5c87ea822abe7bd7ff1c3de770665388d98