Migrate from Karma to jasmine-browser-runner

[alexgibson]

Description

Both Karma and Karma Runner are now deprecated: karma-runner/karma-jasmine#334

"For browser-based unit testing solutions, karma recommends Web Test Runner and jasmine-browser-runner."

It's probably worth us trying to migrate to jasmine-browser-runner, since our tests are already written using Jamsine.

https://jasmine.github.io/setup/browser.html

There's a tutorial here that is mainly React focused, however it includes an example of writing a webpack config to first compile tests before running them: https://jasmine.github.io/tutorials/react_with_browser

If things don't work out, then Web Test Runner is another option.

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Success Criteria

• Front-end tests are migrated from Karma to jasmine-browser-runner