message: auth-backend: use correct interface in factory return type
diff: @@ -18,8 +18,6 @@ import express from 'express';
  import { Logger } from 'winston';
  import { TokenIssuer } from '../identity';
  import { Config } from '@backstage/config';
  -import { OAuthProvider } from '../lib/OAuthProvider';
  -import { SamlAuthProvider } from './saml/provider';
  export type OAuthProviderOptions = {
  /**
  @@ -174,7 +172,7 @@ export type AuthProviderFactory = (
  envConfig: Config,
  logger: Logger,
  issuer: TokenIssuer,
  -) => OAuthProvider | SamlAuthProvider | undefined;
  +) => AuthProviderRouteHandlers | undefined;
  export type AuthResponse<ProviderInfo> = {
  providerInfo: ProviderInfo;
  