favgroups: fix add to favgroup not working.

Fix the Add to Favgroup button not working when the user only has 1
favgroup.

app/javascript/src/javascripts/favorite_groups.js

@@ -1,3 +1,5 @@
+import Rails from "@rails/ujs";
+
 let FavoriteGroup = {};
 
 FavoriteGroup.initialize_all = function() {
@@ -23,8 +25,9 @@ FavoriteGroup.initialize_add_to_favgroup_dialog = function() {
 FavoriteGroup.open_favgroup_dialog = function(e) {
   if ($(".add-to-favgroup").length === 1) {
     // If the user only has one favorite group we don't need to ask which group to add the post to.
-    $(".add-to-favgroup").click();
-  } else if ($(".add-to-favgroup").length > 1) {
+    let favgroup = $(".add-to-favgroup").get(0);
+    Rails.fire(favgroup, "click");
+  } else {
     $("#add-to-favgroup-dialog").dialog("open");
   }
   e.preventDefault();