Fix the KisimageSignalRouterTest

Either an update to Qt broke testing unregistered types, or
this test has always been broken, or some other change to
the KisImageSignalRouter class made it necessary that the
arguments were registered with qRegisterMetaType...

But KoColorProfile and KoColorSpace cannot be registered
with qRegisterMetaType because they are abstract classes,
so we cannot check those signals in this test.