PEAR-1577 - Fix slow unit tests

[amlehman]

Description

1. I added a slow test reporter to identify slow tests
2. Mocked out fetch in tests to prevent tests from using requests
3. Investigated slowest tests. I didn't find any unmocked requests. Most of the tests I wasn't able to do much about their slowness because it was inherent to the tests (testing user operations that needed waits, etc). I was able to reduce the time of the slowest test (GenesAndMutationFrequencyAnalysisTool.unit.test.tsx) by a lot though.

Checklist

• Added proper unit tests
• Left proper TODO messages for any remaining tasks
• Scanned for web accessibility with aXe, and mitigated or documented
  flagged issues

Screenshots/Screen Recordings (if Appropriate)

[wteouchicago]

nothing for me to test, but I do see the new info about the slowest tests.