**Description**
In the trigger page, there is a text area to enter (optional) conf json. It would be great if a sample JSON can be provided programatically while defining DAG

**Use case / motivation**

This will improve usability of the UI that triggers a DAG

tests/www/test_views.py
first_name='dag_faker',
                last_name='dag_faker',
                email='dag_fake@fab.org',
                role=dag_no_role,
                password='dag_faker',
            )
        
        dag_read_only_role = self.appbuilder.sm.add_role('dag_acl_read_only')
        if username == 'dag_read_only' and not self.appbuilder.sm.find_user(username='dag_read_only'):
            self.appbuilder.sm.add_user(
                username='dag_read_only',
                first_name='dag_read_only',
                last_name='dag_read_only',
                email='dag_read_only@fab.org',
                role=dag_read_only_role,
                password='dag_read_only',
            )
        
        all_dag_role = self.appbuilder.sm.add_role('all_dag_role')
        if username == 'all_dag_user' and not self.appbuilder.sm.find_user(username='all_dag_user'):
            self.appbuilder.sm.add_user(
                username='all_dag_user',
                first_name='all_dag_user',
                last_name='all_dag_user',
                email='all_dag_user@fab.org',
                role=all_dag_role,
                password='all_dag_user',
            )
        return super().login(username, password)
    def add_permission_for_role(self):