Fix LaunchAnyWhere in AppRestrictionsFragment

If the intent's package equals to the app's package, this intent
will be allowed to startActivityForResult.
But this check is unsafe, because if the component of this intent
is set, the package field will just be ignored. So if we set the
component to any activity we like and set package to the app's
package, it will pass the assertSafeToStartCustomActivity check
and now we can launch anywhere.

Bug: 223578534
Test: robotest and manual verify
Change-Id: I40496105bae313fe5cff2a36dfe329c1e2b5bbe4
(cherry picked from commit 90e095db)