DAGs with required object type param cannot be triggered with default None

### Apache Airflow version 2.11.0 ### If "Other Airflow 2 version" selected, which one? _No response_ ### What happened? If a DAG contains "object" Param having not having default set, then the manual triggering for it doesn't succeed. In this case, If I push "Trigger" button in UI, it just doesn't react (of course this field is filled manually). I noticed that the reason is because the text that I write is not copied into hidden <textare>, and therefore validation error arise, but as this field is hidden, there is no information for user, and its clearly a bug. <img width="1061" height="334" alt="Image" src="https://github.com/user-attachments/assets/8774f114-5092-437c-b810-d51c6149ffed" /> ### What you think should happen instead? There is clearly an error in console probably connected to this issue. ### How to reproduce `from airflow import DAG from airflow.operators.dummy import DummyOperator from airflow.models import Param with DAG( "run-test", …