*_AppDispatchProvider_get_implementation cannot bypass XInitialization

...as SfxAppDispatchProvider implements new-style service
css.frame.AppDispatchProvider that doesn't declare any non-default ctors (which
looks broken, though) and old-style service css.frame.DispatchProvicer.

(And fix the test code to pass in meaningful XInitialization arguments.)

Change-Id: Ifcc32d17f6b96ade2acc40ccdb60f7bad2d503a4
Simplify showKeyConfigTabPage

Change-Id: I31f7dd7ded3d319ba67e38f530128e28c265b7d5