Allow KaiOS apps (origin "app://") to connnect to the WebSocket server

Summary:
Packaged KaiOS apps have "app://" as their origin prefix (see the "origin" section in the documentation - https://developer.kaiostech.com/getting-started/main-concepts/manifest).

Accept WebSocket connections from any "app://" origin, so can connect to Flipper from apps running on KaiOS devices.

Reviewed By: priteshrnandgaonkar

Differential Revision: D26728925

fbshipit-source-id: 05f15fe464bf0dc977665fba1dd2b8d61a399fa6

desktop/app/src/server.tsx

@@ -187,7 +187,8 @@ class Server extends EventEmitter {
         return (
           info.origin.startsWith('chrome-extension://') ||
           info.origin.startsWith('localhost:') ||
-          info.origin.startsWith('http://localhost:')
+          info.origin.startsWith('http://localhost:') ||
+          info.origin.startsWith('app://')
         );
       },
     });