Call onInitializeAccessibilityEvent for PANE events

AxEvents should be intialized.

Bug: 80251305
Test: Verified by displaying notifications which generate pane related
events.
Used testback to display all info related to an event.
Before this fix, much of that info was not annotated, now it is.

Change-Id: I832fee743c69dc16a050f35e733f0742771df245