Close all open views for 1P and 3P launchers

* Previously TaskView was closing task menu view, but
that got removed since launcher was doing that on
state transition.
* Only 1P launcher was doing that and not 3P launcher,
moved call to remove open views to parent class

Test: Invoking split on 3P launcher doesn't result in a crash
Bug: 199342537
Change-Id: I6afbe7640ede362a677e15a33409a7cabdb8cca9