feat: [M3-8570] - Finish sunsetting Gravatar

[mjac0bs]

Description 📝

This is a follow up from M3-8158 (#10859), which informed users with Gravatars of a sunset date of Sept 30 and transitioned users not currently using Gravatars to our new initial and color avatar icon.

This PR will remove Gravatar support for users who still have it on the communicated date.

Changes 🔄

• Deletes a bunch of Gravatar-related components and utils
• Uses our Avatar component only
• Changes the username for system events or opened support tickets from "Linode" to "Akamai"

📸 Preview

Header	Header

Target release date 🗓️

9/30/24

How to test 🧪

Prerequisites

(How to setup test environment)

• Log in as an account with a Gravatar

Verification steps

(How to verify changes)

• Go to the following locations in the app where we render avatars and confirm that you do not see your Gravatar anywhere:
  • Top Menu
  • Notification Center Event
  • Events Landing > Event Table Row
  • User Landing > User Table Row
  • User SSH Key Panel
  • Profile Display
  • Support Ticket Details (test this in dev with a dummy support ticket you comment on)
• Confirm tests pass

As an Author I have considered 🤔

Check all that apply

• [ ] 👀 Doing a self review
• [x] ❔ Our contribution guidelines
• [x] 🤏 Splitting feature into small PRs
• [x] ➕ 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
• [x] 👣 Providing comprehensive reproduction steps
• [ ] 📑 Providing or updating our documentation
• [ ] 🕛 Scheduling a pair reviewing session
• [ ] 📱 Providing mobile support
• [ ] ♿ Providing accessibility support

[github-actions[bot]]

Coverage Report: ✅
Base Coverage: 86.64%
Current Coverage: 86.7%

[mjac0bs]

Made one change (confirmed with UX) to update the username from "Linode" to "Akamai" in the places shown in the PR description. This better matches the Akamai logo and is consistent with our decision to favor "Akamai" branding throughout the app.

[mjac0bs]

Unrelated CI e2e failure on a nodebalancer test + this test predates the component tests, so this is good to merge.