Fix deepClone so we can overwrite with undefined in when we mock kcContext

src/lib/tools/deepClone.ts

@@ -1,3 +1,17 @@
-export function deepClone<T>(arg: T): T {
-    return JSON.parse(JSON.stringify(arg));
+import "minimal-polyfills/Object.fromEntries";
+
+export function deepClone<T>(o: T): T {
+    if (!(o instanceof Object)) {
+        return o;
+    }
+
+    if (typeof o === "function") {
+        return o;
+    }
+
+    if (o instanceof Array) {
+        return o.map(deepClone) as any;
+    }
+
+    return Object.fromEntries(Object.entries(o).map(([key, value]) => [key, deepClone(value)])) as any;
 }