Fix WebUI greeting for qbittorrent-nox

* Check if WebUI is enabled and print an appropriate message otherwise.
* Print an actual runtime server scheme, address and port.

PR #19696.

src/base/http/server.cpp

@@ -181,3 +181,8 @@ void Server::disableHttps()
     m_certificates.clear();
     m_key.clear();
 }
+
+bool Server::isHttps() const
+{
+    return m_https;
+}