message: fix: underscore relationship names for lookup in relationshipLinks
  Also, make getHasManyLink a bit more robust by checking that links for
  the given relationship actually exist in relationshipLinks.
diff: @@ -90,10 +90,15 @@ export default class OsfModel extends Model {
  relationshipName: R,
  ): string {
  const reference = this.hasMany(relationshipName);
  -
  + let url: string | undefined = reference.link();
  + if (!url) {
  // HACK: ember-data discards/ignores the link if an object on the belongsTo side
  // came first. In that case, grab the link where we expect it from OSF's API
  - const url = reference.link() || getRelatedHref(this.relationshipLinks[relationshipName as string]);
  + const relationshipLinks = this.relationshipLinks[underscore(relationshipName as string)];
  + if (relationshipLinks) {
  + url = getRelatedHref(relationshipLinks);
  + }
  + }
  if (!url) {
  throw new Error(`Could not find a link for '${relationshipName}' relationship`);
  }
  