Fix/prettier cost formatting

[sadiqabubakar826-del]

Summary

This PR contains two formatting-only fixes required by Prettier/ESLint that currently block CI:
Make the expect(...).toHaveBeenCalledWith(...) arguments multiline (prettier formatting) in src/monitoring/cost-scheduler.service.spec.ts
Expand an inline ternary used for metric labels into a multi-line object in src/monitoring/cost-tracking.service.ts
Why

The CI job fails on the lint step with prettier/prettier errors (auto-fixable). These changes align the code with the project's prettier rules so the lint step no longer fails and the rest of the pipeline can run.
Files changed

src/monitoring/cost-scheduler.service.spec.ts

Replace single-line expect call with a multiline call: expect(costService.recordHourlyCost).toHaveBeenCalledWith( result.amount, result.billingPeriod, );
src/monitoring/cost-tracking.service.ts

Replace the one-line ternary: const labels = billingPeriod ? { billing_period: billingPeriod } : { billing_period: 'unknown' };
With a multi-line form: const labels = billingPeriod ? { billing_period: billingPeriod, } : { billing_period: 'unknown', };
Testing steps (what I ran / what you should run)

pnpm install
pnpm run lint # eslint --fix will auto-fix many issues
pnpm run lint:ci # run CI lint check
pnpm run typecheck
pnpm run build
pnpm test --testPathPattern="monitoring"
Acceptance checklist

Lint (prettier) no longer fails on changed files
Typecheck passes
Build passes
Related tests pass locally
closes #1037

[RUKAYAT-CODER]

Thank you for contributing to the project.