Fix transition to LOCKSCREEN after hub timeout

This change fixes an issue where after OOBE, timing out from hub to
dream causes keyguard state to incorrectly transition to LOCKSCREEN
state, showing the keyguard clock and charging status over dream. This
was caused by keyguardInteractor#isKeyguardGoingAway not emitting until
keyguard is going away (unlocked) for the first time.

Since this API is already deprecated, this change minimizes the impact
by manually emitting a false value on start on the collection site.

Test: wipe device and flash a new build, verify that timing out from hub
      to dream transitions to DREAMING keyguard state correctly
Bug: 423563289
Flag: EXEMPT bugfix only
Change-Id: I9d95ea8a6aa4241c2adc897c71a87367750b5d47