Instead of overriding the purely virtual
weld::Dialog::SetInstallLOKNotifierHdl in both, the gtk
and the qt weld implementations, have an empty default
implementation right in the weld::Dialog base class instead.
This method is only relevant for the case where
LibreOfficeKit is used.
Change-Id: If4cafb9d9f00ad497fdd35ee9dfbf400bc18301d
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/203188
Tested-by: Jenkins
Reviewed-by: Michael Weghorn <m.weghorn@posteo.de>