#4618 (closed) was closed when a fix was added for alias and sub domains, however main domains using a proxy redirect are still not able to generate or renew Lets Encrypt certificates because they don't have the necessary vhost location to allow the ACME challenge through to the correct directory.
This fix allows sites using redirect=proxy to still generate ACME certificates by not passing the acme requests through to the proxy.
Perhaps we should also consider using this for other features available such as stats, own error documents, SSI and custom directives. These features are still available in the interface yet have no effect on the vhost when redirect=proxy due to line 91: <tmpl_if name='use_proxy' op='!=' value='y'>. It is not very intuitive, and it would be best if either those features were disabled in the interface when redirect=proxy, or ideally, that they would be used when enabled.
Re-closes #4618 (closed)