Update new-installer.sh to use --system flag for pip installation

Author: KillianLucas

installers/new-installer.sh

@@ -20,7 +20,7 @@ fi
 
 # Direct installation using uv with specific Python version
 echo "Installing package..."
-uv pip install --python "$PYTHON_VERSION" "git+$REPO_URL@$BRANCH"
+uv pip install --system --python "$PYTHON_VERSION" "git+$REPO_URL@$BRANCH"
 
 echo
 echo "Installation complete!"