[8.16] [Security assistant] Update conversations api improvement (ela…

…stic#206828) (elastic#206865)

# Backport

This will backport the following commits from `main` to `8.16`:
- [[Security assistant] Update conversations api improvement
(elastic#206828)](elastic#206828)

<!--- Backport version: 9.6.4 -->

### Questions ?
Please refer to the [Backport tool
documentation](https://github.com/sorenlouv/backport)

<!--BACKPORT [{"author":{"name":"Steph
Milovic","email":"[email protected]"},"sourceCommit":{"committedDate":"2025-01-15T20:36:33Z","message":"[Security
assistant] Update conversations api improvement
(elastic#206828)","sha":"56ce5d45c02436fc2cc31b20f1ccf29823bacf59","branchLabelMapping":{"^v9.0.0$":"main","^v8.18.0$":"8.x","^v(\\d+).(\\d+).\\d+$":"$1.$2"}},"sourcePullRequest":{"labels":["release_note:skip","v9.0.0","backport:all-open","Team:Security
Generative AI"],"title":"[Security assistant] Update conversations api
improvement","number":206828,"url":"https://github.com/elastic/kibana/pull/206828","mergeCommit":{"message":"[Security
assistant] Update conversations api improvement
(elastic#206828)","sha":"56ce5d45c02436fc2cc31b20f1ccf29823bacf59"}},"sourceBranch":"main","suggestedTargetBranches":[],"targetPullRequestStates":[{"branch":"main","label":"v9.0.0","branchLabelMappingKey":"^v9.0.0$","isSourceBranch":true,"state":"MERGED","url":"https://github.com/elastic/kibana/pull/206828","number":206828,"mergeCommit":{"message":"[Security
assistant] Update conversations api improvement
(elastic#206828)","sha":"56ce5d45c02436fc2cc31b20f1ccf29823bacf59"}},{"url":"https://github.com/elastic/kibana/pull/206861","number":206861,"branch":"8.17","state":"OPEN"},{"url":"https://github.com/elastic/kibana/pull/206862","number":206862,"branch":"8.x","state":"OPEN"}]}]
BACKPORT-->

x-pack/plugins/elastic_assistant/server/routes/user_conversations/update_route.test.ts

@@ -15,6 +15,7 @@ import {
 } from '../../__mocks__/conversations_schema.mock';
 import { updateConversationRoute } from './update_route';
 import { AuthenticatedUser } from '@kbn/core-security-common';
+import expect from 'expect';
 
 describe('Update conversation route', () => {
   let server: ReturnType<typeof serverMock.create>;
@@ -28,6 +29,7 @@ describe('Update conversation route', () => {
   } as AuthenticatedUser;
 
   beforeEach(() => {
+    jest.clearAllMocks();
     server = serverMock.create();
     ({ clients, context } = requestContextMock.createTools());
 
@@ -151,5 +153,27 @@ describe('Update conversation route', () => {
         `messages.0.role: Invalid enum value. Expected 'system' | 'user' | 'assistant', received 'invalid'`
       );
     });
+
+    // validate id is correct, check happens on L71 in update_route.ts
+    test('validates id is correct', async () => {
+      const request = requestMock.create({
+        method: 'put',
+        path: ELASTIC_AI_ASSISTANT_CONVERSATIONS_URL_BY_ID,
+        body: {
+          ...getUpdateConversationSchemaMock(),
+          id: 'invalid-id',
+        },
+        params: { id: 'real-id' },
+      });
+      await server.inject(request, requestContextMock.convertContext(context));
+
+      expect(
+        clients.elasticAssistant.getAIAssistantConversationsDataClient.updateConversation
+      ).toHaveBeenCalledWith(
+        expect.objectContaining({
+          conversationUpdateProps: expect.objectContaining({ id: 'real-id' }),
+        })
+      );
+    });
   });
 });

x-pack/plugins/elastic_assistant/server/routes/user_conversations/update_route.ts

@@ -66,7 +66,7 @@ export const updateConversationRoute = (router: ElasticAssistantPluginRouter) =>
             });
           }
           const conversation = await dataClient?.updateConversation({
-            conversationUpdateProps: request.body,
+            conversationUpdateProps: { ...request.body, id },
           });
           if (conversation == null) {
             return assistantResponse.error({