refactor(prompt): move runtime/repo info to user message and disable them in eval

[xingyaoww]

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

This PR send runtime/repo info as user message to the LLM, and repurpose use_microagent flag to enable_prompt_extensions and disable it by default in evaluation.

Quick eval here on 100 instances from SWE-Bench Verified (w/ 30 max turns) - at least no degradation & slightly better (could due to randomness though)

• main: 37/100
• this PR: 39/100

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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:9ee18fd-nikolaik   --name openhands-app-9ee18fd   docker.all-hands.dev/all-hands-ai/openhands:9ee18fd

[xingyaoww]

Quick eval here on 100 instances from SWE-Bench Verified (w/ 30 max turns) - at least no degradation & slightly better (could due to randomness though)
main: 37/100
this PR: 39/100

[rbren]

Confirmed this is working as expected!