Moving testWidgets from TaplTestsLauncher3 to TaplWorkspaceTest

Also, I'm taking advange of this change to update the name of
OopTaplOpenCloseAllApps to follow the standard TaplOpenCloseAllApps
and I'm also moving testPressBack to TaplOpenCloseAllApps since is
similar to the other methods in that class.

Bug: 298234173
Test: atest TaplWorkspaceTest

Change-Id: Ie933828baedf48b45e55f20853e238ecc6a594bd