Utility to determine if client is PWA

Summary: This is currently used in multiple places, let's put it under utils.

Reviewed By: aigoncharov

Differential Revision: D50883125

fbshipit-source-id: ee161a035cd01ca73a2521f813c4b397aa647037

desktop/flipper-ui-core/src/index.tsx

@@ -12,3 +12,5 @@ export {RenderHost, getRenderHostInstance} from 'flipper-frontend-core';
 export {startFlipperDesktop} from './startFlipperDesktop';
 
 export {Icon} from './utils/icons';
+
+export {isPWA} from './utils/pwa';

desktop/flipper-ui-core/src/utils/pwa.tsx

@@ -0,0 +1,12 @@
+/**
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @format
+ */
+
+export const isPWA = () => {
+  return window.matchMedia('(display-mode: standalone)').matches;
+};