avoid SocketTimeoutException by higher interval

[mahibi]

set websocket ping interval from 10s to 30s to avoid too many of these errors:

2026-09-04 09:46:30.920 17696-26274 WebSocketInstance com.nextcloud.talk2EError : WebSocket 261462868 (Fix with AI) java.net.SocketTimeoutException: sent ping but didn't receive pong within 10000ms (after 2 successful ping/pongs)
	at okhttp3.internal.ws.RealWebSocket.writePingFrame$okhttp(RealWebSocket.kt:563)
	at okhttp3.internal.ws.RealWebSocket$initReaderAndWriter$lambda$3$$inlined$schedule$1.runOnce(TaskQueue.kt:219)
	at okhttp3.internal.concurrent.TaskRunner.runTask(TaskRunner.kt:116)
	at okhttp3.internal.concurrent.TaskRunner.access$runTask(TaskRunner.kt:42)
	at okhttp3.internal.concurrent.TaskRunner$runnable$1.run(TaskRunner.kt:65)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1100)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
	at java.lang.Thread.run(Thread.java:1572)

followup of #6543

🏁 Checklist

• ⛑️ Tests (unit and/or integration) are included or not needed
• 🔖 Capability is checked or not needed
• 🔙 Backport requests are created or not needed: /backport to stable-xx.x
• 📅 Milestone is set
• 🌸 PR title is meaningful (if it should be in the changelog: is it meaningful to users?)

🤖 AI (if applicable)

• The content of this PR was partly or fully generated using AI

[mahibi]

/backport to stable-25.0.x

[github-actions]

APK file: https://github.com/nextcloud/talk-android/actions/runs/33851144137/artifacts/9928557685
To test this change/fix you can simply download above APK file and install and test it in parallel to your existing Nextcloud app.
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