Remove VIRTUAL_DISPLAY_FLAG_OWN_DISPLAY_GROUP as a default flag.

This will update the default behaviour of DisplayGroup assignment for
Virtual Devices and assign them to the device display group by default.

Bug: 205343547
Test: atest CreateVirtualDisplayTest
Change-Id: I128010d4399eebbbbd3b36b5cb4f10a8372bb6a7
6 files changed