refactor: [M3-8059] - Clean up Main Content Banner

[bnussman-akamai]

Description 📝

Refactors the MainContentBanner to be simpler, clean, and self-contained 🧹

(I'm doing this because I want to clean up and attempt to improve performance index.tsx, App.tsx, and MainContent.tsx)

Changes 🔄

• Adds unit tests 🧪
• Removes random utils placed in MainContent.tsx 🗑️
• Removes extra state and uses preferences directly 👤 (this is fine because preferences optimistically update)

Preview 📷

Warning

I did make minor UI changes to the banner in efforts to simplify the styles

How to test 🧪

• I included a mock flag in MainContentBanner.tsx you can use to test the banner 🏴
• Verify styles look good on all viewports 🎨
• Check my code for quality and test coverage 🔍

As an Author I have considered 🤔

• 👀 Doing a self review
• ❔ Our contribution guidelines
• 🤏 Splitting feature into small PRs
• ➕ Adding a changeset
• 🧪 Providing/Improving test coverage
• 🔐 Removing all sensitive information from the code and PR description
• 🚩 Using a feature flag to protect the release
• 👣 Providing comprehensive reproduction steps
• 📑 Providing or updating our documentation
• 🕛 Scheduling a pair reviewing session
• 📱 Providing mobile support
• ♿ Providing accessibility support

[bnussman-akamai]

The diff is kind of crazy. The only significant changes here are:

• Remove extra util functions 🗑️
• Move position of <MainContentBanner />

[github-actions]

Coverage Report: ✅
Base Coverage: 81.82%
Current Coverage: 82%