Provide referrer package with respect to package visibility

Otherwise the app can easily get the caller package name by
Activity#getReferrer() with removing intent extra or use
reflection to get Activity#mReferrer directly.

Bug: 191954233
Test: atest ActivityTaskSupervisorTests#testFilteredReferred
Change-Id: I59bfa69ae19e3bec8d9619fbdae3626675fb0d26