Propagate virtual display states to SurfaceFlinger

Reverting the change to ignore FLAG_NEVER_BLANK. We still want the
private non-mirror displays to remain always ON. So only initializing
the state to UNKNOWN if the display is NOT never blank.

Bug: 371125136
Test: presubmit
Flag: android.companion.virtualdevice.flags.correct_virtual_display_power_state
Change-Id: Id9dfaf4a3a3acf2c780fe9f60bcf30b14133be1d