Add more parallel jobs to CI for jest

What does this MR do and why?

Add more parallel jobs to CI for jest

It seems like it has been a while since we've looked at the execution time of our jest jobs.

• jest currently has a median of 22 minute run time, when we have a target of 15 minutes. Looking at a few example pipelines, the tests actually seem to be well distributed. Usually the steps before and after the execution take about 2 minutes, the actual execution takes 20 minutes. 20 minutes * 7 = 140 / (15 - 2) = 10.76. Rounding this up a little to account for future growth seems reasonable.
• jest-as-if-foss Same argument, just that the median is more than 30 minutes.

Screenshots or screen recordings

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How to set up and validate locally

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MR acceptance checklist

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