[Filters][Fixed] We must return 1 object

Wrong in previous patch

kibot/fil_base.py

@@ -342,7 +342,7 @@ def solve_filter(names, target_name, default=None, is_transform=False):
         elif isinstance(names, str):
             # User provided, but only one, make a list
             if names == '_none':
-                return [DummyFilter()]
+                return DummyFilter()
             names = [names]
         # Here we should have a list of strings
         filters = []