change: [M3-8322] - Add Design Update Global Notification Banner

[abailly-akamai]

Description 📝

This PR adds a new dismissible banner for the upcoming design/token updates.

The banner needs to be a little dynamic, featuring the two following variations:

{
  "enabled": true,
  "key": "design-tokens-7-9-2024",
  "link": "https://www.linode.com/docs/guides/an-overview-of-the-cloud-manager"
}

{
  "enabled": false,
  "key": "design-tokens-7-9-2024",
  "link": "https://www.linode.com/docs/guides/an-overview-of-the-cloud-manager"
}

The key is meant to give us the ability to re-introduce the banner for future updates (since it is generic) when people have dismissed it already.

Changes 🔄

• Create new feature flag
• Implement banner

Target release date 🗓️

7/8 2024

Preview 📷

How to test 🧪

The flag is currently only enabled in development

Verification steps

• Verify Cloud Manager Design Updates Banner configuration in LD
• Pull code locally and confirm banner + linkage + dismissible state

As an Author I have considered 🤔

Check all that apply

• 👀 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

[dwiley-akamai]

Code review ✅
Banner contents & dismissibility ✅

[github-actions]

Coverage Report: ✅
Base Coverage: 82.18%
Current Coverage: 82.18%

[bnussman-akamai]

Banner looks good ✅

[bnussman-akamai]

Is enabled needed if this is a toggleable flag?

[abailly-akamai]

This is our standard now for JSON flags now.

[bnussman-akamai]

Should this text be in the flag in case we need to change it?

If I were a Linode customer and saw We are improving the Cloud Manager experience for our users., I'd get triggered because I expect the Cloud Manager experience to be improving at all times. I feel like as this sits currently, we're telling users we're doing the bare minimum.

Maybe it should say We are improving Cloud Manager's visual experience for our users. to hint at the design changes?

[abailly-akamai]

This is the the copy that was provided and vetted by our marketing folks, so I am going to leave it at that.