**Description**
In the trigger page, there is a text area to enter (optional) conf json. It would be great if a sample JSON can be provided programatically while defining DAG

**Use case / motivation**

This will improve usability of the UI that triggers a DAG

airflow/www/views.py
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import copy
import itertools
import json
import logging
import math
import socket
import sys
import traceback
from collections import defaultdict
from datetime import datetime, timedelta
from json import JSONDecodeError
from operator import itemgetter
from typing import Dict, List, Optional, Tuple
from urllib.parse import parse_qsl, unquote, urlencode, urlparse
import lazy_object_proxy
import nvd3
import sqlalchemy as sqla
import yaml
from flask import (
    Markup,
    Response,