[Enhancement]: Handle GH token refresh inside runtime

[malhotra5]

End-user friendly description of the problem this fixes or functionality that this introduces

• 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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Give a summary of what the PR does, explaining any non-trivial design decisions

The GH token can expire inside the runtime (either during the session or when returning to one after a long time). This PR does the following for remote runtimes only

• Checks incoming CmdRunActions that are attempting to use $GITHUB_TOKEN
• Before executing the incoming command, it will first perform export GITHUB_TOKEN={token} where the token is fetched from GitHubService (this diff explains this exact behavior)

This ensures that the latest Github token has been exported to the env BEFORE any Github API request is executed by the agent

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Link of any specific issues this addresses

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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:639eb03-nikolaik   --name openhands-app-639eb03   docker.all-hands.dev/all-hands-ai/openhands:639eb03

[xingyaoww]

LGTM!

[xingyaoww]

nit: maybe we could just do:

kwargs = {}
if runtime_cls == RemoteRuntime:
    kwargs['user_id'] = self.user_id

And then pass **kwargs in runtime_cls constructor to reduce some code duplication