chore: remove unused imports

Signed-off-by: Manish Dait <daitmanish88@gmail.com>

Author: manishdait

src/hiero_sdk_python/client/client.py

@@ -12,7 +12,6 @@
 from dotenv import load_dotenv
 
 from hiero_sdk_python.account.account_id import AccountId
-from hiero_sdk_python.channels import _UserAgentInterceptor
 from hiero_sdk_python.crypto.private_key import PrivateKey
 from hiero_sdk_python.hapi.mirror import (
     consensus_service_pb2_grpc as mirror_consensus_grpc,