Don't collect coverage on every Jest run
We don't need to collect coverage on every yarn jest, and it gets in the way when running yarn jest --watch.
Just run it on the build.
Test Plan: yarn jest, yarn jest --collectCoverage
Reviewers: bengotow, alangenfeld, sashank, prha
Reviewed By: bengotow
Differential Revision: https://dagster.phacility.com/D4667