feat: Created Unit Tests for CSS Color Variables Alignment with Figma Token JSON

[brianacnguyen]

Description

• This PR seeks to add unit tests to brand color tokens, light theme tokens, and dark theme tokens

Related issues

Fixes: #612

Manual testing steps

1. run yarn jest src/css

Screenshots/Recordings

Before

After

• Brand colors test passing

• Brand colors when there's a discrepancy between json and css

• Theme colors test passing

• Theme colors when there's a hex discrepancy between json and css

• Theme colors when there's a brand color discrepancy between json and css

Pre-merge author checklist

• I’ve followed MetaMask Coding Standards.
• I've clearly explained what problem this PR is solving and how it is solved.
• I've linked related issues
• I've included manual testing steps
• I've included screenshots/recordings if applicable
• I’ve included tests if applicable
• I’ve documented my code using JSDoc format if applicable
• I’ve applied the right labels on the PR (see labeling guidelines). Not required for external contributors.
• I’ve properly set the pull request status:
  • In case it's not yet "ready for review", I've set it to "draft".
  • In case it's "ready for review", I've changed it from "draft" to "non-draft".

Pre-merge reviewer checklist

• I've manually tested the PR (e.g. pull and build branch, run the app, test code being changed).
• I confirm that this PR addresses all acceptance criteria described in the ticket it closes and includes the necessary testing evidence such as recordings and or screenshots.

[georgewrmarshall]

LGTM! Left one non-blocking comment to understand the linting ignores

[metamaskbot]

Builds ready [ccecf0c]

Storybook: Storybook

[georgewrmarshall]

LGTM! 🧪 💯 This is going to be a game changer for catching incorrect CSS color tokens during updates. Nice work!