Show work lock confirmation in a task overlay

WorkLockActivity is added on top of each task that has any work
activity when the profile is locked. This activity is a task
overlay meaning it stays on top of other activities. It then starts
ConfirmDeviceCredentialActivity, also as an overlay because
otherwise it will sink under WorkLockActivity. But when CDCA
launches CofirmLockPattern, it is not set as an overlay and as a
result is not visible. These CLs add a boolean extra to instruct
CDCA to launch CLP (or other activities) as an overlay.

Bug: 271840143
Bug: 234002331
Test: manual, with TestDPC setting password reset token.
Change-Id: Ib3f82279cdc8b070c3fb716232459c8315c59602