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
from airflow.exceptions import DuplicateTaskIdFound
    execution_date = pendulum.parse("20200101")
    with pytest.raises(DuplicateTaskIdFound, match=r".* 'task1' .*"):
        with DAG("test_duplicate_group_id", start_date=execution_date):
            _ = DummyOperator(task_id="task1")
            with TaskGroup("task1"):
                pass
    with pytest.raises(DuplicateTaskIdFound, match=r".* 'group1' .*"):
        with DAG("test_duplicate_group_id", start_date=execution_date):
            _ = DummyOperator(task_id="task1")
            with TaskGroup("group1", prefix_group_id=False):
                with TaskGroup("group1"):
                    pass
    with pytest.raises(DuplicateTaskIdFound, match=r".* 'group1' .*"):
        with DAG("test_duplicate_group_id", start_date=execution_date):
            with TaskGroup("group1", prefix_group_id=False):
                _ = DummyOperator(task_id="group1")
    with pytest.raises(DuplicateTaskIdFound, match=r".* 'group1.downstream_join_id' .*"):
        with DAG("test_duplicate_group_id", start_date=execution_date):
            _ = DummyOperator(task_id="task1")
            with TaskGroup("group1"):
                _ = DummyOperator(task_id="downstream_join_id")
    with pytest.raises(DuplicateTaskIdFound, match=r".* 'group1.upstream_join_id' .*"):
        with DAG("test_duplicate_group_id", start_date=execution_date):
            _ = DummyOperator(task_id="task1")
            with TaskGroup("group1"):
                _ = DummyOperator(task_id="upstream_join_id")