Perform dead code analysis with Knip (#2575)

* Install Knip

* Clarify an import that was confusing Knip

* Fix issues detected by Knip

Including cleaning up some unused code and dependencies, using a React hook that we unintentionally stopped using, and also adding some previously undeclared dependencies.

* Run dead code analysis in lint script and CI

---------

Co-authored-by: Timo <toger5@hotmail.de>

src/utils/array.ts

@@ -1,44 +0,0 @@
-/*
-Copyright 2023 New Vector Ltd
-
-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.
-*/
-
-/**
- * Gets the index of the last element in the array to satsify the given
- * predicate.
- */
-// TODO: remove this once TypeScript recognizes the existence of
-// Array.prototype.findLastIndex
-export function findLastIndex<T>(
-  array: T[],
-  predicate: (item: T, index: number) => boolean,
-): number | null {
-  for (let i = array.length - 1; i >= 0; i--) {
-    if (predicate(array[i], i)) return i;
-  }
-
-  return null;
-}
-
-/**
- * Counts the number of elements in an array that satsify the given predicate.
- */
-export const count = <T>(
-  array: T[],
-  predicate: (item: T, index: number) => boolean,
-): number =>
-  array.reduce(
-    (acc, item, index) => (predicate(item, index) ? acc + 1 : acc),
-    0,
-  );

src/utils/matrix.ts

@@ -246,38 +246,6 @@ export function sanitiseRoomNameInput(input: string): string {
   return input;
 }
 
-/**
- * XXX: What is this trying to do? It looks like it's getting the localpart from
- * a room alias, but why is it splitting on hyphens and then putting spaces in??
- * @param roomId
- * @returns
- */
-export function roomNameFromRoomId(roomId: string): string {
-  return roomId
-    .match(/([^:]+):.*$/)![1]
-    .substring(1)
-    .split("-")
-    .map((part) =>
-      part.length > 0 ? part.charAt(0).toUpperCase() + part.slice(1) : part,
-    )
-    .join(" ")
-    .toLowerCase();
-}
-
-export function isLocalRoomId(roomId: string, client: MatrixClient): boolean {
-  if (!roomId) {
-    return false;
-  }
-
-  const parts = roomId.match(/[^:]+:(.*)$/)!;
-
-  if (parts.length < 2) {
-    return false;
-  }
-
-  return parts[1] === client.getDomain();
-}
-
 interface CreateRoomResult {
   roomId: string;
   alias?: string;