workspace: Add count group flag in windowCount workspace selector prop (#5499)

* Add groupCount workspace selector prop

* Intergrate groupCount with windowCount

src/desktop/Window.cpp

@@ -852,6 +852,7 @@ void CWindow::destroyGroup() {
             return;
         }
         m_sGroupData.pNextWindow = nullptr;
+        m_sGroupData.head        = false;
         updateWindowDecos();
         return;
     }