[FIX] web: fix NavBar currentAppSections getter patch

After OWL next was merged, an error popped up while patching the Navbar
currentAppSections getter, coming from the Enterprise NavBar render.
A setter was added on the Navbar component to allow for the patch.

See merge commit for more information.

task-2687506

addons/web/static/src/webclient/navbar/navbar.js

@@ -84,6 +84,10 @@ export class NavBar extends Component {
         );
     }
 
+    // This dummy setter is only here to prevent conflicts between the
+    // Enterprise NavBar extension and the Website NavBar patch.
+    set currentAppSections(_) {}
+
     get systrayItems() {
         return systrayRegistry
             .getEntries()