Extend VirtualDisplayActivityScenarioRule to use secure display

We need to use a secure display in
HidePointerIconOnSecureWindowScreenshotTest in cts-root. To prevent
duplication this CL adds an option to use secure dispplay to launch
specified activity.

Test: atest HidePointerIconOnSecureWindowScreenshotTest
Bug: 319611243
FLAG: TEST_ONLY
Change-Id: I187868f6a263538ca65cf35777bdc011c170fe5f
1 file changed