Rename idp hinting parameter

src/app/user.service.ts

@@ -303,7 +303,7 @@ export class UserService {
 
   public login(idp?: IdP): void {
     const redirect = (idp: IdP) => {
-      window.location.href = '/?idp=' + encodeURIComponent(idp.issuer_uri);
+      window.location.href = '/?idphint=' + encodeURIComponent(idp.issuer_uri);
     };
 
     if (idp != undefined) {