fix: [validation] Fixed an issue with the unique attribute validation rule blocking legitimate use-cases

- adding an attribute with a matching pair or category/type/value in an existing object-contained attribute would be incorrectly flagged as violating the attribute uniqueness rule

app/Model/Attribute.php

@@ -777,7 +777,8 @@ class Attribute extends AppModel {
 			'Attribute.event_id' => $eventId,
 			'Attribute.type' => $type,
 			'Attribute.category' => $category,
-			'Attribute.deleted' => 0
+			'Attribute.deleted' => 0,
+			'Attribute.object_id' => 0
 		);
 		$conditions = array_merge ($conditions, $value);
 		if (isset($this->data['Attribute']['id'])) {