Upgrade TypeScript to 4.9.5

I want to use the `satsifies` operator introduced in 4.9 [1].

Ran `npm install typescript@4.9.5 typedoc@latest`, and then upgraded
@types/node to ^18.0.0, to fix [2].

The TypeScript upgrade introduced one compilation error, which I’ve
fixed here.

I’m targeting the v2 integration branch (which uses the latest webpack)
since trying to upgrade TypeScript on `main` is giving some webpack
errors that don’t seem worth trying to understand.

[1] https://www.typescriptlang.org/docs/handbook/release-notes/typescript-4-9.html#the-satisfies-operator
[2] microsoft/TypeScript#51567

package.json

@@ -32,7 +32,7 @@
   "devDependencies": {
     "@ably/vcdiff-decoder": "1.0.4",
     "@types/crypto-js": "^4.0.1",
-    "@types/node": "^15.0.0",
+    "@types/node": "^18.0.0",
     "@types/request": "^2.48.7",
     "@types/ws": "^8.2.0",
     "@typescript-eslint/eslint-plugin": "^5.14.0",
@@ -68,8 +68,8 @@
     "ts-loader": "^9.4.2",
     "tsconfig-paths-webpack-plugin": "^4.0.1",
     "tslib": "^2.3.1",
-    "typedoc": "^0.23.8",
-    "typescript": "^4.6.4",
+    "typedoc": "^0.24.7",
+    "typescript": "^4.9.5",
     "webpack": "^5.79.0",
     "webpack-cli": "^5.0.1"
   },

src/common/lib/util/utils.ts

@@ -169,7 +169,7 @@ export function arrIntersect<T>(arr1: Array<T>, arr2: Array<T>): Array<T> {
   return result;
 }
 
-export function arrIntersectOb<T>(arr: Array<T>, ob: Record<string, unknown>): T[] {
+export function arrIntersectOb(arr: Array<string>, ob: Record<string, unknown>): string[] {
   const result = [];
   for (let i = 0; i < arr.length; i++) {
     const member = arr[i];