Remove codeql build artifacts and update .gitignore

Co-authored-by: ithewei <26049660+ithewei@users.noreply.github.com>

Author: Copilot

.gitignore

@@ -78,3 +78,5 @@ Release
 CMakeFiles
 CMakeCache.txt
 cmake_install.cmake
+_codeql_build_dir/
+_codeql_detected_source_root