Add a new ImeTracker request when dispatching controls, if not statsToken available

In some cases, the statsToken that is stored in ImeInsetsSourceProvider, is reset before dispatching the leash. In those cases, we still should track the (show) request. Before dispatching the control, this CL creates a new statsToken if there is none stored.

Bug: 393298465
Bug: 383466954
Flag: android.view.inputmethod.refactor_insets_controller
Test: None, logs only
Change-Id: Ib77ff13af2d63f3e149b9da95c8a905a9e44161f