Remove feature_favourite_messages as it is has been abandoned for now (#11097)

* Remove `feature_favourite_messages` as it is has been abandoned for now

* i18n

* Fix test

* Remove unused css

src/hooks/useFavouriteMessages.ts

@@ -1,43 +0,0 @@
-/*
-Copyright 2022 The Matrix.org Foundation C.I.C.
-
-Licensed under the Apache License, Version 2.0 (the "License");
-you may not use this file except in compliance with the License.
-You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE-2.0
-
-Unless required by applicable law or agreed to in writing, software
-distributed under the License is distributed on an "AS IS" BASIS,
-WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-See the License for the specific language governing permissions and
-limitations under the License.
-*/
-
-import { useState } from "react";
-
-const favouriteMessageIds = JSON.parse(localStorage?.getItem("io_element_favouriteMessages") ?? "[]") as string[];
-
-export default function useFavouriteMessages(): {
-    toggleFavourite: (eventId: string) => void;
-    isFavourite: (eventId: string) => boolean;
-} {
-    const [, setX] = useState<string[]>();
-
-    //checks if an id already exist
-    const isFavourite = (eventId: string): boolean => favouriteMessageIds.includes(eventId);
-
-    const toggleFavourite = (eventId: string): void => {
-        isFavourite(eventId)
-            ? favouriteMessageIds.splice(favouriteMessageIds.indexOf(eventId), 1)
-            : favouriteMessageIds.push(eventId);
-
-        //update the local storage
-        localStorage.setItem("io_element_favouriteMessages", JSON.stringify(favouriteMessageIds));
-
-        // This forces a re-render to account for changes in appearance in real-time when the favourite button is toggled
-        setX([]);
-    };
-
-    return { isFavourite, toggleFavourite };
-}