ui: fix network page crash

old-commit-hash: 6136868557

selfdrive/ui/qt/widgets/controls.h

@@ -165,7 +165,7 @@ private:
     p.setPen(Qt::gray);
     for (int i = 0; i < inner_layout.count() - 1; ++i) {
       QWidget *widget = inner_layout.itemAt(i)->widget();
-      if (widget->isVisible()) {
+      if (widget == nullptr || widget->isVisible()) {
         QRect r = inner_layout.itemAt(i)->geometry();
         int bottom = r.bottom() + inner_layout.spacing() / 2;
         p.drawLine(r.left() + 40, bottom, r.right() - 40, bottom);