Use Intl.DateTimeFormat instead of moment for date formatting

ts/util/resolveCanonicalLocales.ts

@@ -0,0 +1,14 @@
+// Copyright 2023 Signal Messenger, LLC
+// SPDX-License-Identifier: AGPL-3.0-only
+
+export function resolveCanonicalLocales(locales: Array<string>): Array<string> {
+  return Intl.getCanonicalLocales(
+    locales.flatMap(locale => {
+      try {
+        return Intl.getCanonicalLocales(locale);
+      } catch {
+        return 'en';
+      }
+    })
+  );
+}