[Lens] unskip flaky test (elastic#190419)

## Summary

Fixes elastic#164623

x-pack/test/functional/apps/lens/group1/ad_hoc_data_view.ts

@@ -73,6 +73,14 @@ export default function ({ getService, getPageObjects }: FtrProviderContext) {
     expect(await dataViews.isAdHoc()).to.be(true);
   };
 
+  const waitForPageReady = async () => {
+    await PageObjects.header.waitUntilLoadingHasFinished();
+    await retry.waitFor('page ready after refresh', async () => {
+      const queryBarVisible = await testSubjects.exists('globalQueryBar');
+      return queryBarVisible;
+    });
+  };
+
   describe('lens ad hoc data view tests', () => {
     it('should allow building a chart based on ad hoc data view', async () => {
       await setupAdHocDataView();
@@ -225,9 +233,7 @@ export default function ({ getService, getPageObjects }: FtrProviderContext) {
       const [lensHandle] = await browser.getAllWindowHandles();
       await browser.switchToWindow(lensHandle);
     });
-
-    // Failing: See https://github.com/elastic/kibana/issues/164623
-    it.skip('should navigate to discover from embeddable correctly', async () => {
+    it('should navigate to discover from embeddable correctly', async () => {
       const [lensHandle] = await browser.getAllWindowHandles();
       await browser.switchToWindow(lensHandle);
       await PageObjects.header.waitUntilLoadingHasFinished();
@@ -247,6 +253,7 @@ export default function ({ getService, getPageObjects }: FtrProviderContext) {
         'new'
       );
 
+      await PageObjects.header.waitUntilLoadingHasFinished();
       await checkDiscoverNavigationResult();
 
       await browser.closeCurrentWindow();
@@ -256,6 +263,7 @@ export default function ({ getService, getPageObjects }: FtrProviderContext) {
 
       // adhoc data view should be persisted after refresh
       await browser.refresh();
+      await waitForPageReady();
       await checkDiscoverNavigationResult();
 
       await browser.closeCurrentWindow();