KeyGestureEvent support to launch applications

This CL is pre-requisite to move modifier based app launch
bookmarks to KeyGestureController.

Bug: 358569822
Test: atest ModifierShortcutTests
Flag: com.android.hardware.input.use_key_gesture_event_handler
Change-Id: I7100a77e68788df513a0b6c334cdc20cd165f301