Toggleable: Add "T operator->() const"

This will be needed by MainWorkflow.

Signed-off-by: Hugo Beauzée-Luyssen <hugo@beauzee.fr>

src/Tools/Toggleable.hpp

@@ -44,6 +44,11 @@ class   Toggleable
         }
         T   operator->()
         {
+//            Q_ASSERT_X( m_activated == true, "Toggleable<T>::operator->", "Pointer is deactivated" );
+            return m_ptr;
+        }
+        T   operator->() const
+        {
 //            Q_ASSERT_X( m_activated == true, "Toggleable<T>::operator->", "Pointer is deactivated" );
             return m_ptr;
         }