repair selection change tracking

forgot to emit the change signal in a number of scenarios. this then
broke actually changing the order and removing items from the selection
because the signal is used to forward the current selection list to the
KConfigSkeleton. by not emitting the signal in all change scenarios we'd
effectively never update the stringlist inside the skeleton causing noop
saves.

kcms/translations/translationsmodel.cpp

@@ -164,6 +164,7 @@ void TranslationsModel::move(int from, int to)
     // only very few languages will be selected and thus visible when a move occurs.
     beginResetModel();
     m_selectedLanguages.move(from, to);
+    Q_EMIT selectedLanguagesChanged(m_selectedLanguages);
     endResetModel();
 }
 
@@ -180,6 +181,7 @@ void TranslationsModel::remove(const QString &languageCode)
     const QModelIndex modelIndex = createIndex(index, 0);
 
     m_selectedLanguages.removeAll(languageCode);
+    Q_EMIT selectedLanguagesChanged(m_selectedLanguages);
     Q_EMIT dataChanged(modelIndex, modelIndex, {IsSelected, SelectionPreference});
 }