change: Improve PR template based on team feedback

[mjac0bs]

Description 📝

Makes small tweaks to our PR template based on team retro discussion on 7/30.

Changes 🔄

• Moves the bottom section of the PR to a HTML comment, hiding it from view but preserving the content
  • This means we don't have to manually delete it from all our PRs
• Adds a checkbox underneath the Changes section as an attempt at quick visual confirmation whether changes are customer-facing
  • Adding this because we have so many projects with feature flags in various states; I'm open to feedback on it!

Target release date 🗓️

N/A

Preview 📷

Verification steps

(How to verify changes)

• Read the diff
• Provide your input

Author Checklists

As an Author, to speed up the review process, I 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

• I have read and considered all applicable items listed above.

As an Author, before moving this PR from Draft to Open, I confirmed ✅

• All tests and CI checks are passing
• TypeScript compilation succeeded without errors
• Code passes all linting rules

[mjac0bs]

@bill-akamai Do you want to add your changes re: request for videos for multi-step processes to this PR?

[coliu-akamai]

thanks @mjac0bs!

[bill-akamai]

@mjac0bs That's ok - I had just made a separate PR here: #12608