Reinstate USER_PRESENT for ConnectivityService

Reverts half of commit 89e7a696
Reverts parts of commit 9a5f4853

Lockdown VPN still needs this to start properly on devices without FBE,
such as phones upgraded from M. Without listening to USER_PRESENT the
first unlock of keystore may get missed, since USER_UNLOCKED is sent too
soon to be useful.

Bug: 34587043
Change-Id: If7a2f5a3173b0f6856244a5f7904bf00c9a5b5e7