Remove unused imports

Author: lgluszek

libs/labelbox/src/labelbox/data/serialization/ndjson/label.py

@@ -2,7 +2,7 @@
 import copy
 from itertools import groupby
 from operator import itemgetter
-from typing import Generator, List, Tuple, Union, Iterator, Dict
+from typing import Generator, List, Tuple, Union
 from uuid import uuid4
 
 from pydantic import BaseModel