The OculusOpenXRLoader module is only required on Android but it should be possible to reference it from any project\plugin that doesn't target that platform.
The user that found the problem is using the MetaXR plugin which supports Win64 and Android. One of it's module depends on OculusOpenXRLoader. The customer created an IB that only had Win64 support. This lead to a compilation failure as the OculusOpenXRLoader.build.cs file was missing.
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-347014 in the post.