Fix for issue where exit session intermittently does not return to splash

[tofarr]

Fix for issue where exit session intermittently does not return to splash

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Exiting the session triggers a change of the token from some value to null, which triggers a disconnect, which triggers a reconnect. With this change, we no longer disconnect when the token changes to null.

Testing

Since this is caused by a race condition, reproduction is intermittent. I've found a reliable way to reproduce the issue is to start a new session with a simple prompt, wait for the task to finish, refresh the page, and then click the "Exit Project" button. Before the fix, OpenHands would not return to the splash screen but instead start a new session.

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:fdddb5b-nikolaik   --name openhands-app-fdddb5b   docker.all-hands.dev/all-hands-ai/openhands:fdddb5b

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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:22e459f-nikolaik   --name openhands-app-22e459f   docker.all-hands.dev/all-hands-ai/openhands:22e459f