[Security Solution][AI Assistant] Handle conflicts during the bulk update (#233288)

## Summary

Part of
Epic: elastic/security-team#12768
Meta: elastic/security-team#13657

In my [previous PR](#232288), I
accidentally removed "retry on conflict"
[logic](https://github.com/elastic/kibana/pull/232288/files#r2305375978).

These changes add a retry logic on bulk update conflicts. For that we
use a `retry_on_conflict` option
https://www.elastic.co/docs/api/doc/elasticsearch/operation/operation-bulk#operation-bulk-body-application-json-update-retry_on_conflict.
The retry count is set to 3 to match previous behaviour.

cc @stephmilovic

Author: e40pud

x-pack/solutions/security/plugins/elastic_assistant/server/ai_assistant_data_clients/conversations/index.test.ts

@@ -179,6 +179,7 @@ describe('AIAssistantConversationsDataClient', () => {
           _id: '04128c15-0d1b-4716-a4c5-46997ac7f3bd',
           _index: 'test-index',
           _source: true,
+          retry_on_conflict: 3,
         },
       },
       {

x-pack/solutions/security/plugins/elastic_assistant/server/lib/data_stream/documents_data_writer.ts

@@ -215,13 +215,14 @@ export class DocumentsDataWriter implements DocumentsDataWriter {
           _id: document.id,
           _index: responseToUpdate?.hits.hits.find((c) => c._id === document.id)?._index,
           _source: true,
+          retry_on_conflict: 3,
         },
       },
       getUpdateScript(document, updatedAt),
     ]);
   };
 
-  private getDeletedocumentsQuery = async (
+  private getDeleteDocumentsQuery = async (
     documentsToDelete: string[],
     authenticatedUser?: AuthenticatedUser
   ) => {
@@ -274,7 +275,7 @@ export class DocumentsDataWriter implements DocumentsDataWriter {
 
     const documentDeletedBody =
       params.documentsToDelete && params.documentsToDelete.length > 0
-        ? await this.getDeletedocumentsQuery(params.documentsToDelete, params.authenticatedUser)
+        ? await this.getDeleteDocumentsQuery(params.documentsToDelete, params.authenticatedUser)
         : [];
 
     const documentUpdatedBody =