fix: correctly increment order counter after user-provided order

When user provides a specific signing order, the next auto-assigned
order should be the provided value + 1.

Changed condition from > to >= and set currentOrder to userProvidedOrder + 1
instead of just userProvidedOrder.

This ensures proper order sequencing when mixing user-provided and
auto-assigned orders.

Signed-off-by: Vitor Mattos <1079143+vitormattos@users.noreply.github.com>

Author: vitormattos

lib/Service/SequentialSigningService.php

@@ -54,8 +54,8 @@ public function determineSigningOrder(?int $userProvidedOrder): int {
 		}
 
 		if ($userProvidedOrder !== null) {
-			if ($userProvidedOrder > $this->currentOrder) {
-				$this->currentOrder = $userProvidedOrder;
+			if ($userProvidedOrder >= $this->currentOrder) {
+				$this->currentOrder = $userProvidedOrder + 1;
 			}
 			return $userProvidedOrder;
 		}