Certificate detected as not used when it is redirected

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
When an SSL certificate is being used in "redirection host", the status column in the certificates section shows as "not used".

Nginx Proxy Manager Version
2.13.5

To Reproduce
Steps to reproduce the behavior:

1. Go to Hosts > Redirection Host
2. Create o select "Let's Encrypt" to redirect.
3. Go to Certificates section.
4. See error

Expected behavior
If the certificate is being used in both proxy host and redirection hosts, the certificate will appear as in use.

Screenshots

Operating System
Docker

Reproduce the issue with the jc21/nginx-proxy-manager:latest Docker image by creating a Hosts > Redirection Host with a Let's Encrypt certificate, then compare the certificate status with its usage in proxy hosts. Trace the certificate usage calculation from the Certificates section and include redirection hosts in the in-use result; done means a certificate used by either host type is shown as in use.