Fix duplicate events on reinit

[tofarr]

Fix duplicate events on re-initialize

• Include this change in the Release Notes. If checked, you must provide an end-user friendly description for your change below

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The frontend code maintains a variable containing the last event from the event stream on the server received over the socket. It uses this when a reinitialization occurs to make sure that the full event stream is not sent over the socket again.

However, the socket does not just contain events from the event stream - it also contains other pseudo events that do not have an ID - for example:

• {token: "******", status: "ok"}
• {status_update: true, type: "info", id: "STATUS$CONTAINER_STARTED", message: "Container started"}

If one of these happened to be the last event received, then the stream was duplicated.

This PR updates the stream to only store a last event if it has a numeric id.

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#5358

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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:139ba40-nikolaik   --name openhands-app-139ba40   docker.all-hands.dev/all-hands-ai/openhands:139ba40

[enyst]

This makes sense, thank you!

I think Stephan's version may be a little better?