Fix displayIdMirror test

With I18b36dadc43ba1c37f9516ff10d24bb8683c04ac
getDisplayIdToMirror will return INVALID_DISPLAY
if the virtual display has own content. By default
virtual display has own content flag set, unless
VIRTUAL_DISPLAY_FLAG_AUTO_MIRROR is present.

This CL adds VIRTUAL_DISPLAY_FLAG_AUTO_MIRROR
to the virtual displays in the test and also
makes sure there is permission to capture video
set.

Change-Id: I703aee71f526013129c187628809763fa6e946b7
Bug: 302336562
Test: atest DisplayManagerServiceTest#testCreateVirtualDisplay_displayIdToMirror