improve update_brush performance

src/node_panel_stroke.cpp

@@ -629,7 +629,7 @@ void NodePanelStroke::init_controls()
         b->m_tip_opacity = 1.f;
         Canvas::I->m_current_brush = b;
         update_controls();
-        App::I->brush_update();
+        App::I->brush_update(true, true);
     };
 
     update_controls();