Switch from defer to Promise.withResolvers (#29078)

* Switch from defer to PromiseWithResolvers

Signed-off-by: Michael Telatynski <7t3chguy@gmail.com>

* Add modernizr check

Signed-off-by: Michael Telatynski <7t3chguy@gmail.com>

* Iterate

Signed-off-by: Michael Telatynski <7t3chguy@gmail.com>

---------

Signed-off-by: Michael Telatynski <7t3chguy@gmail.com>

src/utils/exportUtils/HtmlExport.tsx

@@ -13,7 +13,6 @@ import { renderToStaticMarkup } from "react-dom/server";
 import { logger } from "matrix-js-sdk/src/logger";
 import escapeHtml from "escape-html";
 import { TooltipProvider } from "@vector-im/compound-web";
-import { defer } from "matrix-js-sdk/src/utils";
 
 import Exporter from "./Exporter";
 import { mediaFromMxc } from "../../customisations/Media";
@@ -302,7 +301,7 @@ export default class HTMLExporter extends Exporter {
         if (hasAvatar) await this.saveAvatarIfNeeded(mxEv);
         // We have to wait for the component to be rendered before we can get the markup
         // so pass a deferred as a ref to the component.
-        const deferred = defer<void>();
+        const deferred = Promise.withResolvers<void>();
         const EventTile = this.getEventTile(mxEv, continuation, deferred.resolve);
         let eventTileMarkup: string;