test: add experimental_features_enabled to session context test fixture

The Zod schema adds a default value for the new optional field,
so the parsed output includes it. Update the test fixture to match.

Author: elias-ba

assets/test/collaborative-editor/types/sessionContext.test.ts

@@ -358,6 +358,7 @@ describe.concurrent('SessionContextResponseSchema', () => {
       webhook_auth_methods: [],
       workflow_template: null,
       has_read_ai_disclaimer: true,
+      experimental_features_enabled: false,
     };
 
     const result = SessionContextResponseSchema.safeParse(validResponse);