Fix adding sticker in media editor

ts/util/loadImage.ts

@@ -0,0 +1,21 @@
+// Copyright 2024 Signal Messenger, LLC
+// SPDX-License-Identifier: AGPL-3.0-only
+
+import { explodePromise } from './explodePromise';
+
+export async function loadImage(src: string): Promise<HTMLImageElement> {
+  const { promise, resolve, reject } = explodePromise<void>();
+
+  const img = new Image();
+  img.addEventListener('load', () => resolve(), { once: true });
+  img.addEventListener(
+    'error',
+    () => reject(new Error('Image failed to load')),
+    { once: true }
+  );
+  img.src = src;
+
+  await promise;
+
+  return img;
+}