talk-android doesn't work without access to google.com

Is your feature request related to a problem? Please describe.
We're using Nextcloud in the network environment, where we don't have access to google.com.
TALK works, when I use it from the browser.
But when I use Android app:

• I'm getting red banner at the top, saying "No connection to server".
• When I try to send message, I'm getting red warning "Connection lost - Sent messages are queued"

Describe the solution you'd like
Enable Android app to work even with restricted network connectivity.

Additional context
I found that banner is shown based on the code in the ScheduledMessagesActivity class:

        val isOnline by networkMonitor.isOnline.collectAsStateWithLifecycle()

which relies on the class NetworkMonitorImpl, which uses android.net.ConnectivityManager and android.net.NetworkCapabilities

I tested with version 24.0.0 RC1, nextcloud-talk-24.0.0RC1.apk

Start by tracing the isOnline state in ScheduledMessagesActivity back through NetworkMonitorImpl, including its use of android.net.ConnectivityManager and NetworkCapabilities. Determine how restricted access to google.com is classified, then verify that Talk no longer shows a false disconnected state or queues messages when the Nextcloud server is reachable.