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.
tests/utils/test_task_group.py
with TaskGroup("group34") as group34:
                _ = DummyOperator(task_id="task3")
                _ = DummyOperator(task_id="task4")
        with TaskGroup("group6") as group6:
            _ = DummyOperator(task_id="task6")
        task7 = DummyOperator(task_id="task7")
        task5 = DummyOperator(task_id="task5")
        task1 >> group234
        group34 >> task5
        group234 >> group6
        group234 >> task7
    subdag = dag.sub_dag(task_ids_or_regex="task5", include_upstream=True, include_downstream=False)
    assert extract_node_id(task_group_to_dict(subdag.task_group)) == {
        'id': None,
        'children': [
            {
                'id': 'group234',
                'children': [
                    {
                        'id': 'group234.group34',
                        'children': [
                            {'id': 'group234.group34.task3'},
                            {'id': 'group234.group34.task4'},
                            {'id': 'group234.group34.downstream_join_id'},
                        ],
                    },
                    {'id': 'group234.upstream_join_id'},
                ],
            },
            {'id': 'task1'},