Remove shims for Gitlab::Saas in FOSS

The following discussion from !204424 (merged) should be addressed:

• @dstull started a discussion:

  issue:

  This goes against our guidelines of how to structure code.

  See https://docs.gitlab.com/development/ee_features/#do-not-use-saas-only-features-for-functionality-in-ce

  this change should be reverted and we should find another way to handle initializer variance.

  See !192669 (closed) for an example for how to accomplish this in an initializer.

  Spawning a follow-up.