Unlock managed profile keystore when user is unlocked.

With file based encryption when the user unlock the phone,
managed profile is already running (in a locked state). But
on full disk encryption devices, LSS attempts to unlock child
profile straight after unlocking user 0, which fails because
the profile is not yet running.

With this change once the profile gets unlocked (happens after
ActivityManagerService processes START_PROFILES_MSG message)
LSS will attempt to unlock its keystore.

Bug: 64722589
Test: manual, tried FDE and FBE devices with unified challenge.
Change-Id: Ic614cc3c6732a3db6aaf56fef1822e358d742510