Fail hard if request for group or project 404s

If the user has configured group(s) and project(s), hitting a 404 on /api/v4/group/<group_path> or /api/v4/project/<project_path> indicates that the entity does not exist or that the user does not have access to it, which suggests the user misconfigured the tap.

Instead of ignoring these failures (which makes sense for 40x responses on other endpoints), I think we should fail hard so that the user will know that we cannot actually extract data from the group(s)/project(s) they explicitly said they were interested in.