Fix issue #4828: [Bug]: Chat interface empty state flickers for a brief moment until messages load

[openhands-agent]

This pull request fixes #4828.

The issue of empty state UI flickering has been successfully resolved through a targeted fix that addresses the root cause. The solution involved:

Automatic fix generated by OpenHands 🙌

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To run this PR locally, use the following command:

docker run -it --rm   -p 3000:3000   -v /var/run/docker.sock:/var/run/docker.sock   --add-host host.docker.internal:host-gateway   -e SANDBOX_RUNTIME_CONTAINER_IMAGE=docker.all-hands.dev/all-hands-ai/runtime:102c308-nikolaik   --name openhands-app-102c308   docker.all-hands.dev/all-hands-ai/openhands:102c308

[mamoodi]

Gentle ping for @amanape

[amanape]

I'll circle back to this at a later time. There are a few things UI-related consequences with this PR