Add feature flags for Pinecone, Cloudinary, and GitLab OAuth detectors (#4961)

* Add feature flags for new detectors

* Slight rename, ensure the flags are false by default

* Missed a name change

* Turn on new detectors for OSS user

* Instead of only adding flagged detectors when their flag is enabled, remove them when their flag is disabled

* Thank you cursorbot

* Excempt the flagged detectors from a test