ci(834): use circle CI test splitting for cypress

[jps]

#834

What

1. Background - cypress-parallel is unstable at high levels of parallelization
2. Have moved to using the inbuilt circle cli commands to split the tests, and removed cypress-parallel library
3. Tests running at high levels of parallelism without error see both comps and docs for examples.
   The doc site tests run in ~3:40 vs ~6:30, component tests are about the same. A possible extension to this would be to split the components a11y tests as per the docs, this would result in a good speed up as splitting would be more effective.

[pp-serviceaccount]

You can preview these changes on:
Documentation Site: http://ncu-newskit-docs-pr.s3-website-eu-west-1.amazonaws.com/834-try-alternate-splitting-approach
Storybook: http://ncu-newskit-docs-pr.s3-website-eu-west-1.amazonaws.com/834-try-alternate-splitting-approach/storybook

[JohnTParsons]

Makes sense. Should be more stable.

Hopefully this technique integrate well with future nx/rspack/cypress features.