Fix python3.7 compatibility (#4919)

cvat-sdk/cvat_sdk/core/proxies/model_proxy.py

@@ -13,7 +13,6 @@ from typing import (
     Dict,
     Generic,
     List,
-    Literal,
     Optional,
     Tuple,
     Type,
@@ -22,7 +21,7 @@ from typing import (
     overload,
 )
 
-from typing_extensions import Self
+from typing_extensions import Literal, Self
 
 from cvat_sdk.api_client.model_utils import IModelData, ModelNormal, to_json
 from cvat_sdk.core.helpers import get_paginated_collection