fix: port check ignore connection refused error

Author: seriousm4x

backend/networking/ping.go

@@ -77,10 +77,12 @@ func CheckPort(host string, port string) (bool, error) {
 	timeout := 500 * time.Millisecond
 	conn, err := net.DialTimeout("tcp", net.JoinHostPort(host, port), timeout)
 	if err != nil {
-		// treat "host unreachable" and "timeout" as no error
+		// treat "host unreachable", "connection refused" and "timeout" as no error
 		var netErr *net.OpError
 		if errors.As(err, &netErr) {
-			if errors.Is(netErr.Err, syscall.EHOSTUNREACH) || netErr.Timeout() {
+			if errors.Is(netErr.Err, syscall.EHOSTUNREACH) ||
+				errors.Is(netErr.Err, syscall.ECONNREFUSED) ||
+				netErr.Timeout() {
 				return false, nil
 			}
 		}