DisplayEventDispatcher: add DISPLAY_EVENT_CONFIG_CHANGED

Add a new event for display configuration change. This event
will be sent by SF anytime it changes the display config.

Test: Generate DISPLAY_EVENT_CONFIG_CHANGED and observe the log
Bug: 122905403
Change-Id: Ifa473a34d7b313501e5e4e8a67186fb82754fdcd
6 files changed