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
upstream = True
        else:
            upstream = False
        if not self._dag:
            return self.priority_weight
        from airflow.models.dag import DAG
        dag: DAG = self._dag
        return self.priority_weight + sum(
            map(
                lambda task_id: dag.task_dict[task_id].priority_weight,
                self.get_flat_relative_ids(upstream=upstream),
            )
        )
    @cached_property
    def operator_extra_link_dict(self) -> Dict[str, Any]:
        """Returns dictionary of all extra links for the operator"""
        op_extra_links_from_plugin: Dict[str, Any] = {}
        from airflow import plugins_manager
        plugins_manager.initialize_extra_operators_links_plugins()
        if plugins_manager.operator_extra_links is None:
            raise AirflowException("Can't load operators")
        for ope in plugins_manager.operator_extra_links:
            if ope.operators and self.__class__ in ope.operators:
                op_extra_links_from_plugin.update({ope.name: ope})
        operator_extra_links_all = {link.name: link for link in self.operator_extra_links}
        
        operator_extra_links_all.update(op_extra_links_from_plugin)
        return operator_extra_links_all
    @cached_property
    def global_operator_extra_link_dict(self) -> Dict[str, Any]: