Remove unused git imports from generate_board_config.py

The 'import git' and 'from git import RemoteProgress' were unused
(copy-pasted from get_remote_modules.py which does use them). This caused
CI failures because gitpython is not installed in the GitHub Actions
runner environment. Also removed unused Tuple import.

Author: guysoft

src/custompios_core/generate_board_config.py

@@ -2,9 +2,7 @@
 import os
 import yaml
 from pathlib import Path
-from typing import Tuple, Optional, Dict, Any, cast
-import git
-from git import RemoteProgress
+from typing import Optional, Dict, Any, cast
 from common import get_image_config
 import argparse
 import sys