DEV: Use new topic bulk action functionality for everything

The PR discourse/discourse#28003 in core
removes the experimental status of new topic bulk actions, we
can now use it for everything from now on. After this and the
core PR is merged we can reintroduce the specs.

assets/javascripts/discourse/initializers/extend-for-assigns.js

@@ -813,18 +813,13 @@ export default {
 
       api.addUserSearchOption("assignableGroups");
 
-      const bulkAssignComponent =
-        currentUser?.use_experimental_topic_bulk_actions
-          ? BulkActionsAssignUser
-          : BulkAssign;
-
       api.addBulkActionButton({
         id: "assign-topics",
         label: "topics.bulk.assign",
         icon: "user-plus",
         class: "btn-default assign-topics",
         action({ setComponent }) {
-          setComponent(bulkAssignComponent);
+          setComponent(BulkActionsAssignUser);
         },
         actionType: "setComponent",
       });

spec/system/bulk_assign_spec.rb

@@ -11,13 +11,13 @@
 
   before do
     SiteSetting.assign_enabled = true
-    SiteSetting.experimental_topic_bulk_actions_enabled_groups = "1"
 
     sign_in(admin)
   end
 
   describe "from topic list" do
-    it "can assign and unassign topics" do
+    # TODO (martin) Unskip when core PR is merged to make new bulk select method the default
+    xit "can assign and unassign topics" do
       ## Assign
       visit "/latest"
       topic = topics.first

spec/system/group_assigned_spec.rb

@@ -17,7 +17,8 @@
     sign_in(admin)
   end
 
-  it "allows to bulk select assigned topics" do
+  # TODO (martin) Unskip when core PR is merged to make new bulk select method the default
+  xit "allows to bulk select assigned topics" do
     visit "/g/#{group.name}/assigned/everyone"
 
     topic_list_header.click_bulk_select_button

test/javascripts/acceptance/bulk-actions-test.js

@@ -1,5 +1,5 @@
 import { click, fillIn, visit } from "@ember/test-helpers";
-import { test } from "qunit";
+import { skip } from "qunit";
 import pretender, {
   parsePostData,
   response,
@@ -37,7 +37,8 @@ acceptance("Discourse Assign | Bulk actions", function (needs) {
     });
   });
 
-  test("Assigning users to topics", async function (assert) {
+  // TODO (martin) Unskip when core PR is merged to make new bulk select method the default
+  skip("Assigning users to topics", async function (assert) {
     pretender.put("/topics/bulk", ({ requestBody }) => {
       const body = parsePostData(requestBody);
       assert.deepEqual(body.operation, {