fixed added removed in comparewith

lib/handlers/file_upload_api.dart

@@ -666,8 +666,8 @@ extension CompareIterables<T> on Iterable<T> {
     final Set<T> thisSet = this.toSet();
     final Set<T> otherSet = other.toSet();
 
-    final Set<T> added = otherSet.difference(thisSet);
-    final Set<T> removed = thisSet.difference(otherSet);
+    final Set<T> removed = otherSet.difference(thisSet);
+    final Set<T> added = thisSet.difference(otherSet);
 
     return (added, removed);
   }