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
{
                        'id': 'group_a.group_b',
                        'children': [
                            {'id': 'group_a.group_b.task2'},
                            {'id': 'group_a.group_b.task3'},
                            {'id': 'group_a.group_b.task4'},
                            {'id': 'group_a.group_b.downstream_join_id'},
                        ],
                    },
                    {'id': 'group_a.task5'},
                    {'id': 'group_a.upstream_join_id'},
                    {'id': 'group_a.downstream_join_id'},
                ],
            },
            {
                'id': 'group_c',
                'children': [
                    {'id': 'group_c.task6'},
                    {'id': 'group_c.task7'},
                    {'id': 'group_c.task8'},
                    {'id': 'group_c.upstream_join_id'},
                    {'id': 'group_c.downstream_join_id'},
                ],
            },
            {
                'id': 'group_d',
                'children': [
                    {'id': 'group_d.task11'},
                    {'id': 'group_d.task12'},
                    {'id': 'group_d.upstream_join_id'},