FCM credentials [are tested](https://github.com/WalletConnect/echo-server/blob/c6e6d8dd0ca50bb66c55223506fa9e976764eb13/src/handlers/update_fcm.rs#L87) but not APNS credentials [Slack conversation](https://walletconnect.slack.com/archives/C03RU4F6P8A/p1707215914911769)
