Expose correct relay address in federation

Signed-off-by: Thomas Citharel <tcit@tcit.fr>

js/src/types/instance.model.ts

@@ -3,6 +3,7 @@ import { InstanceFollowStatus } from "./enums";
 export interface IInstance {
   domain: string;
   hasRelay: boolean;
+  relayAddress: string | null;
   followerStatus: InstanceFollowStatus;
   followedStatus: InstanceFollowStatus;
   personCount: number;