Resolve multiple CVEs

CVE-2022-39249
CVE-2022-39250
CVE-2022-39251
CVE-2022-39236

src/NamespacedValue.ts

@@ -1,5 +1,5 @@
 /*
-Copyright 2021 The Matrix.org Foundation C.I.C.
+Copyright 2021 - 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.
@@ -14,6 +14,8 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
+import { Optional } from "matrix-events-sdk/lib/types";
+
 /**
  * Represents a simple Matrix namespaced value. This will assume that if a stable prefix
  * is provided that the stable prefix should be used when representing the identifier.
@@ -54,7 +56,7 @@ export class NamespacedValue<S extends string, U extends string> {
 
     // this desperately wants https://github.com/microsoft/TypeScript/pull/26349 at the top level of the class
     // so we can instantiate `NamespacedValue<string, _, _>` as a default type for that namespace.
-    public findIn<T>(obj: any): T {
+    public findIn<T>(obj: any): Optional<T> {
         let val: T;
         if (this.name) {
             val = obj?.[this.name];