the methods and signals were implemenented for compat with libdbusmenu-qt
but KStatusNotifierItem tracks status by itself for example, internal menu
synchronization (e.g. triggering importer action when exporter action is
triggered) can be implemented via the D-Bus adaptor and interface but is
currently not required
Signed-off-by: Ivailo Monev <xakepa10@gmail.com>