chore: delete unused function

[Senna46]

使用していないFunctionを削除 以下のようなスケーラビリティのエラーが出るのを防ぐ

normal_settlements-normal_settlement-onCreate
The request was aborted because there was no available instance. Additional troubleshooting documentation can be found at: https://cloud.google.com/functions/docs/troubleshooting#scalability