Fix: Open notes shortcut is not customizable

In the new KeyGestureEvent design shortcut handlers should not
depend on keycode and modifeir state to handle an event, so that
the shortcut can be customized in shortcut helepr UI.

Bug: 381241291
Test: atest NoteTaskInitializerTest
Flag: EXEMPT bugfix
Change-Id: I6135c5720901ffeefe70082f8d23d4589b52acec