Add xcaudit for test logs in GitHub action

[subdan]

Could you please show how it looks like by temporary adding one warning and one error in the FigmaExport code.

[Alexander-Ignition]

@subdan xcaudit highlights errors and warnings

you can view it in

• Actions Summary
• Pull Request / Checks / Build logs
• Pull Request / Files Changed

[Alexander-Ignition]

Oh I've seen a few flaws

• [x] add shell: bash to GitHub action to correctly handle test crashes
• [x] check and fix duplicate warnings
• [x] make highlighting of fatalError and other asserts

[Alexander-Ignition]

duplication of warnings is a compiler bug https://bugs.swift.org/plugins/servlet/mobile#issue/SR-13640

[Alexander-Ignition]

@subdan I updated xcuadit and failed-pr https://github.com/RedMadRobot/figma-export/pull/95