Allows splitscreen with work & personal version of the same app

This patch makes it so that the user can use splitscreen with work & personal profile versions of the same app, even if the app does not support multi-instance.

Previously, we checked package name to prevent the user from opening 2 versions of the same app if the app did not allow multi-instance. But multi-instance with different user profiles should actually be allowed, since they are essentially 2 independent apps in the system.

Fixed by changing SplitScreenUtils#samePackage() to take in and check userIds as well.

Fixes: 274973415
Test: Manual
Change-Id: I13d80ddda10f08b87971f45a03d3ba2910befb8a