Fix bug with drag-to-split involving work profiles

This patch fixes a bug where the user would unexpectedly create a split with the work profile version of an app when intending to split with the personal profile version.

The bug occurred because RecentTasksController#findTaskInBackground only checked for ComponentName equality, not for userId equality. So when dragging to split, it would accidentally find the background (work) version of the task instead of creating a new (personal) one.

Fixed by adding a check for userId equality.

Fixes: 283021596
Test: Manual
Change-Id: I128f93267af57a74f5a6237d4ad3b841ca194499