Import google/api/annotations.proto for CRM V2

[catherinetcai]

CRM V2 requires the api/annotations proto. The build process in fairapis downloads it in order to build out the protos.

Might be worthwhile to see if it's possible to fork the protoreflect service to include it as a part of the standard import file.

[marshallbrekka]

@catherinetcai I think we can close this. Our own use case has been handled within our protos repo, and the general case has been solved with the multiple import paths