* and stop setting default values in python operator code, so defaults can be set at the server side.

This issue is just for the PR and questions from maintainers. 
airflow/providers/yandex/hooks/yandex.py
"""
    A base hook for Yandex.Cloud related tasks.
    :param connection_id: The connection ID to use when fetching connection info.
    :type connection_id: str
    """
    conn_name_attr = 'yandex_conn_id'
    default_conn_name = 'yandexcloud_default'
    conn_type = 'yandexcloud'
    hook_name = 'Yandex Cloud'
    @staticmethod
    def get_connection_form_widgets() -> Dict[str, Any]:
        """Returns connection widgets to add to connection form"""
        from flask_appbuilder.fieldwidgets import BS3PasswordFieldWidget, BS3TextFieldWidget
        from flask_babel import lazy_gettext
        from wtforms import PasswordField, StringField
        return {
            "extra__yandexcloud__service_account_json": PasswordField(
                lazy_gettext('Service account auth JSON'),
                widget=BS3PasswordFieldWidget(),
                description='Service account auth JSON. Looks like '
                '{"id", "...", "service_account_id": "...", "private_key": "..."}. '