Fix invite-specific join errors not being shown (#32621)

* Fix invite-specific join errors not being shown

* remove horrible non-jest function of getAccountData

* Use an Error

* Always dispatch an Error

* Throw a UserFriendlyError

apps/web/test/test-utils/test-utils.ts

@@ -688,7 +688,6 @@ export function mkStubRoom(
         fetchRoomThreads: jest.fn().mockReturnValue(Promise.resolve()),
         findEventById: jest.fn().mockReturnValue(undefined),
         findPredecessor: jest.fn().mockReturnValue({ roomId: "", eventId: null }),
-        getAccountData: (_: EventType | string) => undefined as MatrixEvent | undefined,
         getAltAliases: jest.fn().mockReturnValue([]),
         getAvatarUrl: () => "mxc://avatar.url/room.png",
         getCanonicalAlias: jest.fn(),
@@ -725,6 +724,7 @@ export function mkStubRoom(
         getRoomUnreadNotificationCount: jest.fn().mockReturnValue(0),
         getVersion: jest.fn().mockReturnValue("1"),
         getBumpStamp: jest.fn().mockReturnValue(0),
+        getAccountData: jest.fn(),
         hasMembershipState: () => false,
         isElementVideoRoom: jest.fn().mockReturnValue(false),
         isSpaceRoom: jest.fn().mockReturnValue(false),