ProjectsSection: rework to use reactive data, Array prop type

Summary of changes

• Move ProjectsSection logic out of WishlistIntake
• Rework ProjectsSection to use reactive data()
• Use Array prop type instead of String
• Move methods from setup() to methods()
• If an "extended" project is selected on page load, expand the list so that the selected project is visible
• Have "All projects" check all checkboxes
• Make the cards themselves be clickable, not just the checkboxes
• Change the template to use cdx-field per Codex recommendation
• Use aria-label and area-labeledby per Codex warnings
• Change storage values to be i18n keys for use in on-wiki messages
• Rework Module:Community_Requests to handle display logic
• Remove unused styles

Bug: T362275