Fix vulnerability that allowed attackers to start arbitary activities

Test: Flashed device and verified dream settings works as expected
Test: Installed APK from bug and verified the dream didn't allow
launching the inappropriate settings activity.
Fixes: 300090204

Change-Id: I146415ad400827d0a798e27f34f098feb5e96422
Merged-In: I6e90e3a0d513dceb7d7f5c59d6807ebe164c5716