Remove split instructions view on split launch success

* We weren't removing the instance of the view
that is created when split initiated from workspace
* Fewer bugs like this once RecentsView + workspace
instructions view are consolidated

Bug: 292590703
Flag: ENABLE_SPLIT_FROM_WORKSPACE_TO_WORKSPACE
Test: Swiping to home after split apps launch
hides the view

Change-Id: I6b5037c024e6e0c456b687bc802076f691a955b2