refactor: convert utils & validations from enzyme to RTL

[tomdavies73]

Proposed behaviour

1. Renames and re-writes all test and test descriptions of test files which do not contain any JSX.
2. Fully re-writes and converts all test files which do contain JSX from enzyme -> RTL.

Current behaviour

All test files are either written in enzyme and or use poor practices.

Checklist

• Commits follow our style guide
• Related issues linked in commit messages if required
• Screenshots are included in the PR if useful
• All themes are supported if required
• Unit tests added or updated if required
• Playwright automation tests added or updated if required
• Storybook added or updated if required
• Translations added or updated (including creating or amending translation keys table in storybook) if required
• Typescript d.ts file added or updated if required
• Related docs have been updated if required

QA

• Tested in provided StackBlitz sandbox/Storybook
• Add new Playwright test coverage if required
• Carbon implementation matches Design System/designs
• UI Tests GitHub check reviewed if required

Additional context

Testing instructions

[nuria1110]

Agree with James' comments, nothing else from me so happy to approve once they've been addressed.

[carbonci]

🎉 This PR is included in version 142.11.7 🎉

The release is available on:

• npm package (@latest dist-tag)
• GitHub release

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