Take the Threads Activity Centre out of labs (#12439)

* Take the TAC out of labs!

Requires https://github.com/matrix-org/matrix-react-sdk/pull/12438
and ideally https://github.com/matrix-org/matrix-react-sdk/pull/12418

* i18n

* Add test method

That's needed now we we don't include threads in the notif count in the tests

* One less labs setting

* Update snapshot

* Disable release announcement

* Unused import

* Fix some screenshots

* Fix all the unread test cases now room unreads don't include threads

* Fix more tests

* Even more test fixes

* Still more test fixes

* Oh goodness, it's more test fixes

* Fix selectors now there are 2 buttons called Threads

* Disable some tests that aren't passing

for reasons that don't appear releated to any of the TAC work, as
per the comment.

* Remove debugging

* Oops, removed too much

src/stores/notifications/RoomNotificationStateStore.ts

@@ -42,8 +42,6 @@ export class RoomNotificationStateStore extends AsyncStoreWithClient<IState> {
     private listMap = new Map<TagID, ListNotificationState>();
     private _globalState = new SummarizedNotificationState();
 
-    private tacEnabled = SettingsStore.getValue("threadsActivityCentre");
-
     private constructor(dispatcher = defaultDispatcher) {
         super(dispatcher, {});
         SettingsStore.watchSetting("feature_dynamic_room_predecessors", null, () => {
@@ -99,7 +97,7 @@ export class RoomNotificationStateStore extends AsyncStoreWithClient<IState> {
      */
     public getRoomState(room: Room): RoomNotificationState {
         if (!this.roomMap.has(room)) {
-            this.roomMap.set(room, new RoomNotificationState(room, !this.tacEnabled));
+            this.roomMap.set(room, new RoomNotificationState(room, false));
         }
         return this.roomMap.get(room)!;
     }