fix: update threshold_config set_config calls

[Errordog2]

Summary

• updates threshold_config.rs to use the current set_config(caller, severity, threshold_minutes, penalty_per_minute, reward_base) API
• removes the now-unused SLAConfig import
• keeps the existing threshold test assertions and scenarios unchanged

Validation

• git diff --check passes locally
• cargo test -p apexchainx_calculator threshold_config --no-default-features could not complete in this Windows environment because the MSVC linker link.exe is not installed

[Icahbod]

Thanks for the cleanup @Errordog2! Quick heads-up before I can merge this: per our contribution guidelines, every PR needs to be linked to an approved tracking issue so maintainers have the context to triage. I don't see a Closes #… (or Fixes #…) reference on this PR, and the body doesn't mention which problem this solves. Could you open or link an issue describing the motivation (e.g. test compilation breakage on the new set_config signature) so reviewers and future contributors can follow the why? Holding off on merging until that's in place.

[Icahbod]

Hi @Errordog2, thanks for the PR. The closest matching issue (#3) is assigned to @aliyuHabibu, so under our author=assignee policy we can't merge this from your handle. Also looks like #56 by @Joeloo1 already addresses the same threshold_config set_config concern. Could you coordinate on the issue, or close this in favor of the existing PR? 🙏