Deleting Active SSL Certificate Breaks All Hosts Using It

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

Deleting a certificate that is currently in use sends NPM into a reboot loop. Similar to #3420

Nginx Proxy Manager Version

2.10.4

To Reproduce
Steps to reproduce the behavior:

1. Configure a proxy host
2. Configure an SSL cert and add it to the above
3. Delete the proxy host
4. NPM will now return "internal error" for any attempted activities (such as swapping hosts to a new certificate); recreating the container presents the below error, where npm-# is the certificate you just deleted.

[emerg] cannot load certificate "/etc/letsencrypt/live/npm-3/fullchain.pem": BIO_new_file() failed

Expected behavior

Either do not allow an actively used certificate to be deleted, or update the nginx.conf files for all hosts using it prior to resolving the delete request.

Operating System

Docker running on Ubuntu server

Additional context

Upon investigating, I found that the sqlite database reflected the new SSL certificate in the certificate table and the hosts I swapped to the new certificate reflected the correct certificate in the proxy_host table, however the nginx .conf files in /proxy_host/ folder still had the path of the old certificate in them. Manually editing these config files and then restarting the container allowed it to start up as expected.

Reproduce the failure with the listed proxy-host and certificate steps using the Docker image, then inspect the certificate and proxy_host database records alongside the generated files in /proxy_host/. Compare those records with the nginx.conf paths shown in the startup error. Done means deleting an in-use certificate no longer leaves hosts referencing a missing certificate, either by preventing deletion or updating all affected configurations.