frontend: remove reserved props from dropdown component

src/assets/bundle.js

@@ -11575,7 +11575,7 @@
     }
   });
   Vue.component("dropdown", {
-    props: ["class", "toggle-class", "ref", "drop", "title"],
+    props: ["toggle-class", "drop", "title"],
     data: function() {
       return { open: false };
     },

src/assets/javascripts/app.ts

@@ -79,7 +79,7 @@ Vue.component('drag', {
 })
 
 Vue.component('dropdown', {
-  props: ['class', 'toggle-class', 'ref', 'drop', 'title'],
+  props: ['toggle-class', 'drop', 'title'],
   data: function() {
     return {open: false}
   },