fix flake8 mistakes

Author: slampy97

ydb/_grpc/grpcwrapper/ydb_coordination_public_types.py

@@ -1,7 +1,7 @@
 from dataclasses import dataclass
 from enum import IntEnum
 import typing
-import ydb
+
 
 if typing.TYPE_CHECKING:
     from ..v4.protos import ydb_coordination_pb2

ydb/coordination/base_coordination_client.py

@@ -1,6 +1,3 @@
-import typing
-from typing import Optional
-
 from ydb import _apis, issues
 from ydb._grpc.grpcwrapper.ydb_coordination_public_types import NodeConfig, NodeDescription