This PR introduces a second source of costs tracking for benchmarks by using a virtual key for each instance id https://github.com/OpenHands/benchmarks/pull/605 (it was already enabled for ACP agents, this enables it for regular OH too). Am validating it with OH runs, hopefully the costs are not too divergent 😅 FYI @millions-crayon-32880

For OH runs we might want to use the recalculating action from time to time. Sometimes LiteLLM costs differ from official costs