cant show html chart version locust 2.4.0

[4672192zq]

Describe the bug

Headless mode cannot view charts-html

Expected behavior

The generated htlm can be displayed normally

Actual behavior

Steps to reproduce

`from locust import HttpUser,TaskSet,between,task,FastHttpUser

from locust import LoadTestShape

headers = {"Content-Type": "application/json", "app_id": "101"}
class UserBehavior(TaskSet):

def on_start(self):
    pass
@task
def test_health(self):
    '''查询全部'''

    url = '/statapi/health'

    with self.client.get(url,catch_response=True,timeout=3) as response:
        # print("=====", response)
        if response.status_code!=200:
            response.failure('Failed!')


def on_stop(self):
    pass

class MyCustomShape(LoadTestShape):

stages = [
    {"time": 10, "users": 100, "spawn_rate": 50},
    {"time": 30, "users": 200, "spawn_rate": 50},

]
def tick(self):
    run_time = self.get_run_time()
    print("run_time:",run_time)
    for stage in self.stages:

        if run_time < stage['time']:
            print('11111',stage['time'])
            tick_data = (stage['users'],stage['spawn_rate'])
            print('tick_data', tick_data)
            return tick_data
    return None


    # return None

class WebsiteUser(FastHttpUser):
tasks = [UserBehavior]

wait_time = between(1, 1)

`

Environment

• OS:
• Python version:3.9
• Locust version: (please dont file issues for anything but the most recent release or prerelease builds)
• Locust command line that you ran:
• Locust file contents (anonymized if necessary):

[AlexisC0de]

in case of environment.shape_class code path, stats_history won't be filled, thus preventing the Charts graph to be displayed in the html report.
It seems that the stats_history runner launch should be moved before start_automatic_run() .

diff --git a/locust/main.py b/locust/main.py
index 9c0bdc2..f5819d2 100644

--- a/locust/main.py
+++ b/locust/main.py
@@ -341,6 +341,8 @@ def main():
         stats_printer_greenlet = gevent.spawn(stats_printer(runner.stats))
         stats_printer_greenlet.link_exception(greenlet_exception_handler)
 
+    gevent.spawn(stats_history, runner)
+
     def start_automatic_run():
         if options.master:
             # wait for worker nodes to connect
@@ -408,8 +410,6 @@ def main():
     if options.csv_prefix:
         gevent.spawn(stats_csv_writer.stats_writer).link_exception(greenlet_exception_handler)
 
-    gevent.spawn(stats_history, runner)
-
     def shutdown():
         """
         Shut down locust by firing quitting event, printing/writing stats and exiting

(this complete commit 08bc7e9)