✨(back) manage streaming with the ai service

We want to handle both streaming or not when interacting with the AI
backend service.

src/frontend/apps/e2e/__tests__/app-impress/utils-common.ts

@@ -14,6 +14,7 @@ export const CONFIG = {
     color: '#8bc6ff',
   },
   AI_FEATURE_ENABLED: true,
+  AI_STREAM: true,
   API_USERS_SEARCH_QUERY_MIN_LENGTH: 3,
   CRISP_WEBSITE_ID: null,
   COLLABORATION_WS_URL: 'ws://localhost:4444/collaboration/ws/',