unable to start/run after updating to 2.14.0

Checklist

• Have you pulled and found the error with jc21/nginx-proxy-manager:latest docker image?
  • Yes
• Are you sure you're not using someone else's docker image?
  • Yes
• Have you searched for similar issues (both open and closed)?
  • Yes

Describe the bug
After updating to 2.14, NPM no longer functions. i cannot access the web UI nor is it proxying requests to existing hosts.

Nginx Proxy Manager Version
cannot get to login page

To Reproduce
Steps to reproduce the behavior:

1. Update image to 2.14 (from a recent version, unfortunately i'm not sure which one)
2. cannot get to web UI, no functioning proxy hosts.

Expected behavior

Screenshots

Operating System
Ubuntu 20.04

Additional context
Docker 28.1.1

From the docker logs:

nginx: [warn] the "listen ... http2" directive is deprecated, use the "http2" directive instead in /data/nginx/proxy_host/1.conf:19
nginx: [warn] protocol options redefined for 0.0.0.0:443 in /data/nginx/proxy_host/11.conf:14
^^^those entries repeated for other configured hosts.
nginx: [emerg] unknown "x_forwarded_scheme" variable

Reproduce the update to the jc21/nginx-proxy-manager:latest image at version 2.14 on Ubuntu 20.04 and start with the Docker logs. Inspect the generated files under /data/nginx/proxy_host/, especially 1.conf and 11.conf, around the unknown x_forwarded_scheme variable. Done means the container starts, the web UI is reachable, and existing proxy hosts work without this emerg error.