Remove PECL extension CI workflow

The continuous integration workflow for testing with the Ray.Aop PECL extension has been removed. This decision may have been made to streamline the CI process or due to changes in project requirements, which render this particular workflow unnecessary. If further testing is required for the PECL extension, alternative methods or new workflows may need to be implemented.

AOPのコードに変化がないのにCIでエラーが出たためにこのワークフローを一時的に外します。ext-aopの方でテストすべきかもしれません。