[Background search] Restore unsaved dashboards (#240067)

## Summary

Closes #227311

Right now if we create a background search of an unsaved dashboard it
doesn't store the panels/references in the saved object, that menas that
we can't really restore it. With this we store them even if the
dashboard isn't saved but I don't have any context on why it wasn't done
like this before so happy to get input on it.

---

#### Background an unsaved dashboard and just open it again

Before


https://github.com/user-attachments/assets/fd282c28-53ea-49dc-b58b-1441e25dfbb1

After


https://github.com/user-attachments/assets/d39fbef0-d9b2-4763-bd10-1db98b4fc667

---

#### Background an unsaved dashboard, remove it and open it again

Before


https://github.com/user-attachments/assets/9c1ba24d-a55f-4176-a409-5070d282110d


After


https://github.com/user-attachments/assets/7d0a4e3e-e213-40f4-9c41-50783a08b2df

---

### Checklist

Check the PR satisfies following conditions. 

Reviewers should verify this PR satisfies this list as well.

- [ ] [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] The PR description includes the appropriate Release Notes section,
and the correct `release_note:*` label is applied per the
[guidelines](https://www.elastic.co/guide/en/kibana/master/contributing.html#kibana-release-notes-process)
- [x] Review the [backport
guidelines](https://docs.google.com/document/d/1VyN5k91e5OVumlc0Gb9RPa3h1ewuPE705nRtioPiTvY/edit?usp=sharing)
and apply applicable `backport:*` labels.

Author: AlexGPlay

src/platform/plugins/shared/dashboard/public/dashboard_app/url/search_sessions_integration.ts

@@ -78,12 +78,11 @@ function getLocatorParams({
   shouldRestoreSearchSession: boolean;
 }): DashboardLocatorParams {
   const savedObjectId = dashboardApi.savedObjectId$.value;
-  const panels = savedObjectId
-    ? (dashboardInternalApi.serializeLayout() as Pick<
-        DashboardLocatorParams,
-        'panels' | 'references'
-      >)
-    : undefined;
+
+  const panels = dashboardInternalApi.serializeLayout() as Pick<
+    DashboardLocatorParams,
+    'panels' | 'references'
+  >;
 
   const { controlGroupInput, controlGroupReferences } = dashboardInternalApi.serializeControls();
 

x-pack/platform/test/search_sessions_integration/tests/apps/dashboard/async_search/index.ts

@@ -38,5 +38,6 @@ export default function ({ loadTestFile, getService, getPageObjects }: FtrProvid
     loadTestFile(require.resolve('./save_search_session'));
     loadTestFile(require.resolve('./save_search_session_relative_time'));
     loadTestFile(require.resolve('./sessions_in_space'));
+    loadTestFile(require.resolve('./unsaved_dashboard'));
   });
 }

x-pack/platform/test/search_sessions_integration/tests/apps/dashboard/async_search/unsaved_dashboard.ts

@@ -0,0 +1,123 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License
+ * 2.0; you may not use this file except in compliance with the Elastic License
+ * 2.0.
+ */
+
+import expect from '@kbn/expect';
+import type { FtrProviderContext } from '../../../../ftr_provider_context';
+
+export default function ({ getService, getPageObjects }: FtrProviderContext) {
+  const testSubjects = getService('testSubjects');
+  const log = getService('log');
+  const searchSessions = getService('searchSessions');
+  const kibanaServer = getService('kibanaServer');
+  const retry = getService('retry');
+  const monacoEditor = getService('monacoEditor');
+
+  const { common, home, timePicker, header, discover, dashboard, searchSessionsManagement } =
+    getPageObjects([
+      'common',
+      'timePicker',
+      'header',
+      'home',
+      'discover',
+      'dashboard',
+      'dashboardControls',
+      'searchSessionsManagement',
+    ]);
+
+  async function addFromLibrary() {
+    await testSubjects.click('dashboardAddTopNavButton');
+    await testSubjects.click('dashboardAddFromLibraryButton');
+    await testSubjects.setValue('savedObjectFinderSearchInput', 'Unsaved dashboard slow query');
+    await testSubjects.click('savedObjectTitleUnsaved-dashboard-slow-query');
+  }
+
+  async function openBackgroundSearchWhenReady() {
+    await retry.waitFor('the background search to be completed', async () => {
+      const _list = await searchSessionsManagement.getList();
+      return _list[0].status === 'complete';
+    });
+
+    const list = await searchSessionsManagement.getList();
+    await list[0].view();
+  }
+
+  describe('saves a search session for unsaved dashboard', () => {
+    describe('with a discover session', () => {
+      // Add the sample dataset
+      before(async () => {
+        await kibanaServer.uiSettings.replace({
+          enableESQL: true,
+        });
+
+        await common.navigateToUrl('home', '/tutorial_directory/sampleData', {
+          useActualUrl: true,
+        });
+        await retry.try(async () => {
+          await home.addSampleDataSet('flights');
+          const isInstalled = await home.isSampleDataSetInstalled('flights');
+          expect(isInstalled).to.be(true);
+        });
+        log.debug('Sample data installed');
+      });
+
+      // Save a slow query to a discover session
+      before(async () => {
+        await common.navigateToApp('discover');
+        await header.waitUntilLoadingHasFinished();
+
+        await timePicker.setCommonlyUsedTime('This_week');
+        await discover.selectTextBaseLang();
+        await monacoEditor.setCodeEditorValue(
+          'FROM kibana_sample_data_flights | LIMIT 1 | WHERE DELAY(1500ms)'
+        );
+        await testSubjects.clickWhenNotDisabledWithoutRetry('querySubmitButton');
+        await discover.waitUntilSearchingHasFinished();
+        await discover.saveSearch('Unsaved dashboard slow query');
+      });
+
+      afterEach(async () => {
+        await common.navigateToApp('dashboard');
+        await testSubjects.click('discard-unsaved-New-Dashboard');
+        await testSubjects.click('confirmModalConfirmButton');
+      });
+
+      it('should be restored when opening from the background search', async () => {
+        await common.navigateToApp('dashboard');
+        await dashboard.clickCreateDashboardPrompt();
+
+        await addFromLibrary();
+        await searchSessions.save({ isSubmitButton: true });
+        await dashboard.waitForRenderComplete();
+
+        await searchSessions.openFlyoutFromToast();
+        await openBackgroundSearchWhenReady();
+
+        await dashboard.verifyNoRenderErrors();
+      });
+
+      describe('when the dashboard is also discarded', async () => {
+        it('should still restore the session', async () => {
+          await common.navigateToApp('dashboard');
+          await dashboard.clickCreateDashboardPrompt();
+
+          await addFromLibrary();
+          await searchSessions.save({ isSubmitButton: true });
+          await dashboard.waitForRenderComplete();
+
+          await common.navigateToApp('dashboard');
+          await testSubjects.click('discard-unsaved-New-Dashboard');
+          await testSubjects.click('confirmModalConfirmButton');
+
+          await searchSessionsManagement.goTo();
+          await openBackgroundSearchWhenReady();
+
+          await dashboard.verifyNoRenderErrors();
+        });
+      });
+    });
+  });
+}