lighthouse

Describe the bug
I have 2 builds with different CLS
Build 1 - CLS = 0.001
Build 2 - CLS = 0.026
When I compare this 2 builds it will not show CLS in metrics (this works with any threshold)

To Reproduce
Steps to reproduce the behavior:

1. Prepare 2 builds with different CLS
2. Compare them

Expected behavior
See CLS diff same way as any other metrics.

*Logs/Screenshots

Some prior art here:

https://github.com/puppeteer/examples/blob/master/verify_sw_caching.js
https://michaljanaszek.com/blog/test-website-performance-with-puppeteer/#cacheAndServiceWorker