[ML] Enable change point detection functional tests (#198702)

## Summary

Closes #178258

Enable change point detection functional tests

### Checklist

- [x] [Unit or functional
tests](https://www.elastic.co/guide/en/kibana/master/development-tests.html)
were updated or added to match the most common scenarios
- [x] [Flaky Test
Runner](https://ci-stats.kibana.dev/trigger_flaky_test_runner/1) was
used on any tests changed

(cherry picked from commit 1411604)

x-pack/plugins/aiops/public/components/change_point_detection/fields_config.tsx

@@ -261,7 +261,7 @@ const FieldPanel: FC<FieldPanelProps> = ({
             disabled: removeDisabled,
           },
         ],
-        'data=test-subj': 'aiopsChangePointDetectionContextMenuPanel',
+        'data-test-subj': 'aiopsChangePointDetectionContextMenuPanel',
       },
       {
         id: 'attachMainPanel',

x-pack/test/functional/apps/aiops/change_point_detection.ts

@@ -16,8 +16,7 @@ export default function ({ getPageObjects, getService }: FtrProviderContext) {
   // aiops lives in the ML UI so we need some related services.
   const ml = getService('ml');
 
-  // Failing: See https://github.com/elastic/kibana/issues/178258
-  describe.skip('change point detection', function () {
+  describe('change point detection', function () {
     before(async () => {
       await esArchiver.loadIfNeeded('x-pack/test/functional/es_archives/ml/ecommerce');
       await ml.testResources.createDataViewIfNeeded('ft_ecommerce', 'order_date');

x-pack/test/functional/services/aiops/change_point_detection_page.ts

@@ -131,6 +131,12 @@ export function ChangePointDetectionPageProvider(
     },
 
     async openPanelContextMenu(panelIndex: number) {
+      // Check if already open
+      const isOpen = await testSubjects.exists('aiopsChangePointDetectionAttachButton');
+      if (isOpen) {
+        return;
+      }
+
       await testSubjects.click(
         `aiopsChangePointPanel_${panelIndex} > aiopsChangePointDetectionContextMenuButton`
       );