Handle virtual display power state in SurfaceFlinger

If the state changes while there's no surface, the new power state is lost. Even though there's no DisplayDevice, there's a proper DisplayDeviceState for that virtual display. Storing the power state there and respecting it when creating the display will work.

This is tied to android::companion::virtualdevice::flags::correct_virtual_display_power_state since that flag controls whether or not to set the power mode of the SurfaceControl for the virtual display (which ultimately feeds into SurfaceFlinger::setPowerMode).

With this change, virtual displays whose PowerMode is OFF will no longer be composited since the correct power mode is now set in SurfaceFlinger (instead of assuming all virtual displays are ON).

Bug: 342681202

Flag: android.companion.virtualdevice.flags.correct_virtual_display_power_state

Test: manually tested with flag on/off with Android Auto Projected

Change-Id: Ib10514da05e277a8ed574c92ff71d2a4d52975b2