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
#
#
#
import pendulum
import pytest
from airflow.models import DAG
from airflow.operators.dummy_operator import DummyOperator
from airflow.utils.task_group import TaskGroup
from airflow.www.views import dag_edges, task_group_to_dict
EXPECTED_JSON = {
    'id': None,
    'value': {
        'label': None,
        'labelStyle': 'fill:#000;',
        'style': 'fill:CornflowerBlue',
        'rx': 5,
        'ry': 5,
        'clusterLabelPos': 'top',
    },
    'tooltip': '',
    'children': [
        {
            'id': 'group234',
            'value': {
                'label': 'group234',
                'labelStyle': 'fill:#000;',
                'style': 'fill:CornflowerBlue',
                'rx': 5,
                'ry': 5,
                'clusterLabelPos': 'top',