KPI: add new build configuration for experimentation

[worldomonation]

Proposed Changes

This PR adds a new build configuration to allow for experimentation without affecting the main E2E builds.

Testing Instructions

Ensure the following:

• [x] Unit Tests
• [x] Code Style

Pre-merge Checklist

• [ ] Have you written new tests for your changes?
• [ ] Have you tested the feature in Simple (P9HQHe-k8-p2), Atomic (P9HQHe-jW-p2), and self-hosted Jetpack sites (PCYsg-g6b-p2)?
• [ ] Have you checked for TypeScript, React or other console errors?
• [ ] Have you used memoizing on expensive computations? More info in Memoizing with create-selector and Using memoizing selectors and Our Approach to Data
• [ ] Have we added the "[Status] String Freeze" label as soon as any new strings were ready for translation (p4TIVU-5Jq-p2)?

Related to https://github.com/Automattic/wp-calypso/issues/66469

[github-actions[bot]]

Calypso Live (direct link)

https://calypso.live?image=registry.a8c.com/calypso/app:build-43153

Jetpack Cloud live (direct link)

https://calypso.live?image=registry.a8c.com/calypso/app:build-43153&env=jetpack

[matticbot]

This PR does not affect the size of JS and CSS bundles shipped to the user's browser.

Generated by performance advisor bot at iscalypsofastyet.com.

[worldomonation]

Cool! In practice, how would this get used?

This would be used to experiment with pushing test results data from TeamCity to an external data store (eg. Grafana/ElasticSearch or S3). Details are here: pciE2j-1mq-p2