[FIX] web: adding toggle to view with studio

Steps to reproduce:
- edit RFQ model with studio
- add a toggle widget to the product list
- activate/deactivate the toggle multiple times on different products

Bug:
sometimes the element on the widget is undefined when trying to rerender

Fix:
check the element is defined before trying to render it

opw-3013024

closes odoo/odoo#106607

X-original-commit: 1b09a631
Signed-off-by: Aaron Bohy (aab) <aab@odoo.com>
Signed-off-by: Walid Hanniche (waha) <waha@odoo.com>

addons/web/static/src/legacy/js/views/basic/basic_renderer.js

@@ -789,6 +789,9 @@ var BasicRenderer = AbstractRenderer.extend(WidgetAdapterMixin, {
         // associated to new widget)
         var self = this;
         def.then(function () {
+            if(!widget.$el){
+                return;
+            }
             // when the caller of renderFieldWidget uses something like
             // this.renderFieldWidget(...).addClass(...), the class is added on
             // the temporary div and not on the actual element that will be