Add loading state to the new room list view (#29725)

* add loading state to view model and spinner to room list vieqw

* Update snapshots and add loading test

* avoid nested ternary operator

* Add room list skeleton loading state

* Fix loading logic

- Create RoomListStoreV3Event as to not conflict with loading event definition in Create RoomListStoreEvent.
- Add a loaded event
- Use it to determine loaded state in useFilteredRooms rather than the update event which gets fired in other cases.

* Fix isLoadingRooms logic

* update snapshots and fix test

* Forcing an empty commit to fix PR

* Fix _components.pcss order

* Fix test that wasn't doing anything

* fix tests

test/unit-tests/stores/room-list-v3/RoomListStoreV3-test.ts

@@ -10,13 +10,12 @@ import { logger } from "matrix-js-sdk/src/logger";
 
 import type { MatrixClient } from "matrix-js-sdk/src/matrix";
 import type { RoomNotificationState } from "../../../../src/stores/notifications/RoomNotificationState";
-import { RoomListStoreV3Class } from "../../../../src/stores/room-list-v3/RoomListStoreV3";
+import { LISTS_UPDATE_EVENT, RoomListStoreV3Class } from "../../../../src/stores/room-list-v3/RoomListStoreV3";
 import { AsyncStoreWithClient } from "../../../../src/stores/AsyncStoreWithClient";
 import { RecencySorter } from "../../../../src/stores/room-list-v3/skip-list/sorters/RecencySorter";
 import { mkEvent, mkMessage, mkSpace, stubClient, upsertRoomStateEvents } from "../../../test-utils";
 import { getMockedRooms } from "./skip-list/getMockedRooms";
 import { AlphabeticSorter } from "../../../../src/stores/room-list-v3/skip-list/sorters/AlphabeticSorter";
-import { LISTS_UPDATE_EVENT } from "../../../../src/stores/room-list/RoomListStore";
 import dispatcher from "../../../../src/dispatcher/dispatcher";
 import SpaceStore from "../../../../src/stores/spaces/SpaceStore";
 import { MetaSpace, UPDATE_SELECTED_SPACE } from "../../../../src/stores/spaces";