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
"""
    This is an alternative syntax to use TaskGroup. It should result in the same TaskGroup
    as using context manager.
    """
    execution_date = pendulum.parse("20200101")
    dag = DAG("test_build_task_group", start_date=execution_date)
    task1 = DummyOperator(task_id="task1", dag=dag)
    group234 = TaskGroup("group234", dag=dag)
    _ = DummyOperator(task_id="task2", dag=dag, task_group=group234)
    group34 = TaskGroup("group34", dag=dag, parent_group=group234)
    _ = DummyOperator(task_id="task3", dag=dag, task_group=group34)
    _ = DummyOperator(task_id="task4", dag=dag, task_group=group34)
    task5 = DummyOperator(task_id="task5", dag=dag)
    task1 >> group234
    group34 >> task5
    assert task_group_to_dict(dag.task_group) == EXPECTED_JSON
def extract_node_id(node, include_label=False):
    ret = {"id": node["id"]}
    if include_label:
        ret["label"] = node["value"]["label"]
    if "children" in node:
        children = []
        for child in node["children"]:
            children.append(extract_node_id(child, include_label=include_label))
        ret["children"] = children
    return ret
def test_build_task_group_with_prefix():