fix(quickstart): do not use gunicorn for wagtail

[stasadev]

The Issue

Wagtail quickstart is flaky. This fix didn't help:

• test(quickstart): fix wagtail hang, reduce job timeout to 60m #8164

---

https://github.com/ddev/ddev/actions/runs/23153267347/job/67260809737

not ok 49 Wagtail quickstart with ddev version v1.25.1-15-g5541feccf
# (from function `assert_output' in file /home/linuxbrew/.linuxbrew/lib/bats-assert/src/assert_output.bash, line 186,
#  in test file docs/tests/wagtail.bats, line 94)
#   `assert_output --partial "server: gunicorn"' failed
# Not trying to remove hostnames from hosts file because DDEV_NONINTERACTIVE=true
#
# -- output does not contain substring --
# substring : server: gunicorn
# output    :
# --
#
#  Container ddev-my-wagtail-site-web Stopping
#  Container ddev-my-wagtail-site-web Stopped
#  Container ddev-my-wagtail-site-web Stopping
#  Container ddev-my-wagtail-site-web Stopped
#  Container ddev-my-wagtail-site-web Removing
#  Container ddev-my-wagtail-site-web Removed
#  Network ddev-my-wagtail-site_default Removing
#  Network ddev-my-wagtail-site_default Removed
# Not trying to remove hostnames from hosts file because DDEV_NONINTERACTIVE=true

How This PR Solves The Issue

Uses https://docs.wagtail.org/en/stable/getting_started/tutorial.html#start-the-server:

-gunicorn mysite.wsgi:application -b 0.0.0.0:8000
+python manage.py runserver 0.0.0.0:8000

Removes changes from:

• test(quickstart): fix wagtail hang, reduce job timeout to 60m #8164

Manual Testing Instructions

Follow Wagtail quickstart

Automated Testing Overview

Release/Deployment Notes