Issue with php.ini and opcache exclude

https://github.com/magento/magento-cloud/blob/5c8b5a2c74d5cc7d035dca09d592215874ff1887/php.ini#L42
`opcache.blacklist_filename="${MAGENTO_CLOUD_APP_DIR}/op-exclude.txt"`

This line has special characters and ends up causing problems in Magento Cloud Docker environments, and unless it is parsed somehow, I would assume it is not working as intended in Magento Cloud.

This was introduced in: https://github.com/magento/magento-cloud/commit/8cfcb8f8ee3fa7afa5dc6bcbe9ce202f74074cce#diff-243dae866e7173c76f8b91864096c15ffcb3aec3699da130eb0b7ef2566fdce3

Additionally, the opcache.txt exclude also is problematic. because it refers to /app/ for all the files which on some environments (pro vs starter vs integration) does not always match. Sometimes the root dir is /app/g34n60jkdr_stg for instance.

Start with php.ini at line 42 and inspect the referenced op-exclude.txt and opcache.txt paths in the Magento Cloud Docker configuration. Compare how the PHP configuration and file paths behave in pro, starter, and integration environments; done means the configuration parses correctly and the intended exclusions resolve to the deployed application path.

Written by the indexing model from the issue text.