Sheet: update commands status when selection is changed

Notice it doesn't cover the case of the context menu actions
 Partially fixes #6744

src/Mod/Spreadsheet/Gui/SheetTableView.cpp

@@ -938,6 +938,12 @@ void SheetTableView::mousePressEvent(QMouseEvent* event)
     QTableView::mousePressEvent(event);
 }
 
+void SheetTableView::selectionChanged(const QItemSelection &selected, const QItemSelection &deselected)
+{
+    Gui::getMainWindow()->updateActions();
+    QTableView::selectionChanged(selected, deselected);
+}
+
 void SheetTableView::edit ( const QModelIndex & index )
 {
     currentEditIndex = index;

src/Mod/Spreadsheet/Gui/SheetTableView.h

@@ -89,6 +89,7 @@ protected:
     bool event(QEvent *event);
     void closeEditor(QWidget *editor, QAbstractItemDelegate::EndEditHint hint);
     void mousePressEvent(QMouseEvent* event);
+    void selectionChanged(const QItemSelection &selected, const QItemSelection &deselected);
 
     void contextMenuEvent (QContextMenuEvent * e);