This helps debugging why an adaptor's method fails to be called.
Example output:
QDBusConnection: couldn't handle call to LaunchCommand: Type not registered with QtDBus in parameter list: QByteArrayList
tests/auto/dbus/qdbusmarshall/tst_qdbusmarshall shows many warnings
after this commit, since it's testing many cases of "no such slot".
Pick-to: 6.0 6.1 5.15
Change-Id: Ic4ddcd91d005555a02d531fc8960aea2c809e20b
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>