Settings 2-pane deep link vulnerabilities

Settings app must not start an deep link Activity if
1. The deep link Activity is not exported.
or
2. Calling package does not have the permission to
   start the deep link Activity.

Bug: 250589026
Test: make RunSettingsRoboTests ROBOTEST_FILTER=SettingsHomepageActivityTest
Change-Id: I9a3bddfa5d9d1d2e924dd6f3e5e07dca6c11664f
Merged-In: I9a3bddfa5d9d1d2e924dd6f3e5e07dca6c11664f