Fix Flake8 Errors in CI #202
Description
Motivation
Flake8 checks were recently added to the CI, and optuna_integration/comet/comet.py and optuna_integration/botorch/botorch.py generate errors. These errors were temporarily ignored, but now the ignore rules should be removed.
ref: Add flake8 in ci #201
Suggestion
Resolve the errors as recommended by Flake8.
Additional context (optional)
No response