DM: Propagate uniqueID when creating virtual displays

This is part of Trunk Stable effort to upstream SF-ARC screen record
capabiliy (undiverging http://ag/20003031) which requires mirroring
virtual displays to be associated with screen capture sessions using
the package name within the unique ID.

Creating virtual display with unique ID specified is optional such that
it doesn't affect existing consumers who don't need it (i.e. av).

Bug: 137375833
Bug: 194863377
Test: atest libsurfaceflinger_unittest
Test: atest DisplayServiceTests
Change-Id: Ib0b162511b08870aebb6a2229581290d16c47b5b