Summary

Fixes a browser relay failure mode where subsequent browser actions could fail with during handling when callers omit for form fields.

Root cause

route required both and for every field. Some callers/relay paths may provide without , causing the server to drop all fields and return .

Fix

• In , default missing to for .
• Keep required.

Tests

• Extended with a regression case: works when field has and no , and passes to Playwright layer.

Fixes #27296.