Acceptance criteria
- Create a class that subscribes to the event hook defined in T346953
- When the hook is called, insert a simple text field which receives the Grant ID. The format is 1234-12345, see T321814.
- The field should be validated and return an error if invalid, see possible error messages on T321814
- The field should have a label reading "Grant ID", see the AC for the label on T321814
- The field should have additional help text to explain its purpose, see the AC on T321814
- The field should have a placeholder, see AC in T321814