Make Notifications more responsive

How to use GitHub

• Please use the 👍 reaction to show that you are interested into the same feature.
• Please don't comment if you have no relevant information to add. It's just extra noise for everyone subscribed to this issue.
• Subscribe to receive notifications on status change and new comments.

Is your feature request related to a problem? Please describe.
Calls in NextCloud Talk Desktop App need up to 55s until the pop-up or any other notification gets displayed, same for messages. Messages are only instant if you joined a chatroom.

Describe the solution you'd like
It would be nice if the app is more responsive in terms of notifications. I think that is not a problem with the backend, because on iOS the notifications for messages or calls are instant (under 5s).

Describe alternatives you've considered
At the moment, as far as I understand the code the app polls for new notifications every ~30s which is just to slow if you really want to answer a call and not call back 1min after.

Additional context
At the moment I am running:
NextCloud Talk Desktop: 1.0.1
Nextcloud 30.0.4
NextCloud Talk 20.1.3

Start by reproducing delayed call and message notifications in Nextcloud Talk Desktop 1.0.1 with the reported Nextcloud and Talk versions, then trace the app's reported roughly 30-second notification polling. Done means calls and messages are delivered promptly rather than waiting up to 55 seconds, with the behavior checked against the iOS comparison described in the issue.