DisplayEventDispatcher: use eConfigChangedDispatch

In order to get DISPLAY_EVENT_CONFIG_CHANGED, eConfigChangedDispatch needs
to be used when creating DisplayEventDispatcher.

Bug: 131688378
Test: adb shell /data/nativetest64/libsurfaceflinger_unittest/libsurfaceflinger_unittest
Test: trigger config change and observe logcat
Change-Id: I0de8037ee5b024b7d9729750f582be919087be41