message: auth-backend: Use stringifyEntityRef helper
diff: */
  import {
  - UserEntity,
  - serializeEntityRef,
  RELATION_MEMBER_OF,
  + stringifyEntityRef,
  + UserEntity,
  } from '@backstage/catalog-model';
  import { TokenParams } from '../../identity';
  export function getEntityClaims(entity: UserEntity): TokenParams['claims'] {
  - const userRef = serializeEntityRef(entity);
  - if (typeof userRef !== 'string') {
  - throw new Error(
  - `Failed to serialize user entity ref, ${JSON.stringify(userRef)}`,
  - );
  - }
  + const userRef = stringifyEntityRef(entity);
  const membershipRefs =
  entity.relations
  ?.filter(r => r.type === RELATION_MEMBER_OF)
  - .map(r => {
  - const ref = serializeEntityRef(r.target);
  - if (typeof ref !== 'string') {
  - throw new Error(
  - `Failed to serialize relation entity ref, ${JSON.stringify(ref)}`,
  - );
  - }
  - return ref;
  - }) ?? [];
  + .map(r => stringifyEntityRef(r.target)) ?? [];
  return {
  sub: userRef,
  