[DisplayEventDispatcher] Move DisplayEventDispatcher into libgui.

Original source file was at frameworks/base/libs/androidfw.

For now, libgui will be its new home so that the graphics module can
depend on libandroidfw without pulling in libgui.

Bug: 142760698
Test: builds
Change-Id: Iea51e24ffb11a6ad79ad91a9e887f5e326705f1b