[Search] [Playground] Omit question from session state (elastic#189716)

## Summary

Bug within session persistence where it may persist the question into
form state which in turn gets persisted into localstorage. This change
omits the question from the session state.

### Checklist

Delete any items that are not applicable to this PR.

- [ ] Any text added follows [EUI's writing
guidelines](https://elastic.github.io/eui/#/guidelines/writing), uses
sentence case text and includes [i18n
support](https://github.com/elastic/kibana/blob/main/packages/kbn-i18n/README.md)
- [ ]
[Documentation](https://www.elastic.co/guide/en/kibana/master/development-documentation.html)
was added for features that require explanation or tutorials
- [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
- [ ] [Flaky Test
Runner](https://ci-stats.kibana.dev/trigger_flaky_test_runner/1) was
used on any tests changed
- [ ] Any UI touched in this PR is usable by keyboard only (learn more
about [keyboard accessibility](https://webaim.org/techniques/keyboard/))
- [ ] Any UI touched in this PR does not create any new axe failures
(run axe in browser:
[FF](https://addons.mozilla.org/en-US/firefox/addon/axe-devtools/),
[Chrome](https://chrome.google.com/webstore/detail/axe-web-accessibility-tes/lhdoppojpmngadmnindnejefpokejbdd?hl=en-US))
- [ ] If a plugin configuration key changed, check if it needs to be
allowlisted in the cloud and added to the [docker
list](https://github.com/elastic/kibana/blob/main/src/dev/build/tasks/os_packages/docker_generator/resources/base/bin/kibana-docker)
- [ ] This renders correctly on smaller devices using a responsive
layout. (You can test this [in your
browser](https://www.browserstack.com/guide/responsive-testing-on-local-server))
- [ ] This was checked for [cross-browser
compatibility](https://www.elastic.co/support/matrix#matrix_browsers)

x-pack/plugins/search_playground/public/providers/form_provider.test.tsx

@@ -130,6 +130,8 @@ describe('FormProvider', () => {
 
     act(() => {
       setValue(ChatFormFields.prompt, 'New prompt');
+      // omit question from the session state
+      setValue(ChatFormFields.question, 'dont save me');
     });
 
     await waitFor(() => {

x-pack/plugins/search_playground/public/providers/form_provider.tsx

@@ -36,7 +36,10 @@ const getLocalSession = (storage: Storage): PartialChatForm => {
   }
 };
 
-const setLocalSession = (state: PartialChatForm, storage: Storage) => {
+const setLocalSession = (formState: PartialChatForm, storage: Storage) => {
+  // omit question from the session state
+  const { question, ...state } = formState;
+
   storage.setItem(LOCAL_STORAGE_KEY, JSON.stringify(state));
 };
 

x-pack/test/functional/page_objects/search_playground_page.ts

@@ -47,6 +47,12 @@ export function SearchPlaygroundPageProvider({ getService }: FtrProviderContext)
           },
         });
       },
+
+      async expectInSession(key: string, value: string | undefined): Promise<void> {
+        const session = (await browser.getLocalStorageItem(SESSION_KEY)) || '{}';
+        const state = JSON.parse(session);
+        expect(state[key]).to.be(value);
+      },
     },
     PlaygroundStartChatPage: {
       async expectPlaygroundStartChatPageComponentsToExist() {
@@ -151,6 +157,20 @@ export function SearchPlaygroundPageProvider({ getService }: FtrProviderContext)
         await testSubjects.existOrFail('summarizationPanel');
       },
 
+      async updatePrompt(prompt: string) {
+        await testSubjects.setValue('instructionsPrompt', prompt);
+      },
+
+      async updateQuestion(question: string) {
+        await testSubjects.setValue('questionInput', question);
+      },
+
+      async expectQuestionInputToBeEmpty() {
+        const questionInput = await testSubjects.find('questionInput');
+        const question = await questionInput.getAttribute('value');
+        expect(question).to.be.empty();
+      },
+
       async sendQuestion() {
         await testSubjects.setValue('questionInput', 'test question');
         await testSubjects.click('sendQuestionButton');

x-pack/test_serverless/functional/test_suites/search/search_playground/playground_overview.ts

@@ -192,6 +192,16 @@ export default function ({ getPageObjects, getService }: FtrProviderContext) {
             'You are a fireman in london that helps answering question-answering tasks.'
           );
         });
+
+        it("saves a session to localstorage when it's updated", async () => {
+          await pageObjects.searchPlayground.session.setSession();
+          await browser.refresh();
+          await pageObjects.searchPlayground.PlaygroundChatPage.navigateToChatPage();
+          await pageObjects.searchPlayground.PlaygroundChatPage.updatePrompt("You're a doctor");
+          await pageObjects.searchPlayground.PlaygroundChatPage.updateQuestion('i have back pain');
+          await pageObjects.searchPlayground.session.expectInSession('prompt', "You're a doctor");
+          await pageObjects.searchPlayground.session.expectInSession('question', undefined);
+        });
       });
 
       after(async () => {