Airflow v2.0b3
 Kubernetes v1.19.3

Discovered issue while testing KubernetesPodOperator (haven't tested with other operator).
If I create a multiline string using """ """", add some variables inside (Jinja templating), then use this string as an argument to KubernetesPodOperator:
- In Graph View DAG is not visible (just gray area where it should be a digraph);
- in browser's web console i see the following error:

`Uncaught TypeError: node is undefined
    preProcessGraph http://localhost:8080/static/dist/dagre-d3.min.js:103
    preProcessGraph http://localhost:8080/static/dist/dagre-d3.min.js:103
    fn http://localhost:8080/static/dist/dagre-d3.min.js:103
    call http://localhost:8080/static/dist/d3.min.js:3
    draw http://localhost:8080/graph?dag_id=mydag&execution_date=mydate
    expand_group http://localhost:8080/graph?dag_id=mydag&execution_date=mydate
    <anonymous> http://localhost:8080/graph?dag_id=mydag&execution_date=mydate`

Tree view works without issues in this case. The DAG succeeds.
airflow/models/baseoperator.py
"""@property: extra links for the task"""
        return list(
            set(self.operator_extra_link_dict.keys()).union(self.global_operator_extra_link_dict.keys())
        )
    def get_extra_links(self, dttm: datetime, link_name: str) -> Optional[Dict[str, Any]]:
        """
        For an operator, gets the URL that the external links specified in
        `extra_links` should point to.
        :raise ValueError: The error message of a ValueError will be passed on through to
            the fronted to show up as a tooltip on the disabled link
        :param dttm: The datetime parsed execution date for the URL being searched for
        :param link_name: The name of the link we're looking for the URL for. Should be
            one of the options specified in `extra_links`
        :return: A URL
        """
        if link_name in self.operator_extra_link_dict:
            return self.operator_extra_link_dict[link_name].get_link(self, dttm)
        elif link_name in self.global_operator_extra_link_dict:
            return self.global_operator_extra_link_dict[link_name].get_link(self, dttm)
        else:
            return None
    @classmethod
    def get_serialized_fields(cls):