refactor: remove unused nullcontext imports

Author: isasmendiagus

src/scanoss/scanners/folder_hasher.py

@@ -1,6 +1,5 @@
 import json
 import os
-from contextlib import nullcontext
 from dataclasses import dataclass
 from pathlib import Path
 from typing import Dict, List, Literal, Optional

src/scanoss/scanners/scanner_hfh.py

@@ -25,7 +25,6 @@
 import json
 import threading
 import time
-from contextlib import nullcontext
 from typing import Dict, Optional
 
 from progress.spinner import Spinner