Send full refs as parameters from the frontend

We should always send back full refs as parameters from the frontend when possible.

An example of a place where we send back a ref name instead of full ref is when manually running a pipeline.

The primary goal is to make sure that Project#protected_for? always receives a full ref.

Implementation Guide

This method gets called from Gitlab::Ci::Pipeline::Chain::Command, which gets built in CreatePipelineService which receives parameters from the controller which receives parameters from the fronted. All of those places send back just the ref name. Fixing this requires those parts of the frontend to be reworked into sending back full refs.