Split `verifyWCTNotExecuted` into handler specific methods

`veriftyWCTNotExecuted` checks that the default transition handler does
not execute on a WCT. This is currently used universally to verify all
non executed WCT transitions in `DesktopTasksControllerTest`. However,
`DesktopTasksController` uses different transition handlers for different scenarios meaning `verifyWCTNotExecuted` can check the wrong handler causing a test to falsely pass.

Instead we should have methods to verify a WCT is not executed for each
specific transition handler that can be used accordingly.

Fixes: 346756122
Test: atest WMShellUnitTests:DesktopTasksControllerTest
Change-Id: I592f8c9718a9ce7f61e7c1ecfa4a30e62ed42779