Introduce isStagingServer util method

ts/util/isStagingServer.ts

@@ -0,0 +1,17 @@
+// Copyright 2024 Signal Messenger, LLC
+// SPDX-License-Identifier: AGPL-3.0-only
+
+import { Environment, getEnvironment } from '../environment';
+import { isStaging } from './version';
+
+export function isStagingServer(
+  serverUrl = window.SignalContext.config.serverUrl
+): boolean {
+  if (getEnvironment() === Environment.Staging) {
+    return true;
+  }
+  if (isStaging(window.getVersion())) {
+    return true;
+  }
+  return /staging/i.test(serverUrl);
+}