Don't prepare in-window animations if leaveKeyguardOpenOnHide.

This resulted in a blank launcher as we prepared for, but
then never started, the in-window unlock animations, since
the keyguar was remaining open over the Launcher.

Fixes: 231396336
Test: pull down shade with show sensitive content only enabled; using pin/pattern unlock
Change-Id: I236e46e410225d47404015d08cbfd9777727a84c