Blocks explicit activity starts when not visible

This change blocks explicit launches of packages the caller does not
have access to, while continuing to allow implicit launches.

Test: atest AppEnumerationTests android.appsecurity.cts.EphemeralTest
Fixes: 148657387
Change-Id: Ie7641619ab6e8d153cf4f923cbc1e7c5f2bb8e97
1 file changed