UI - Upgrade to React 19

[ryanhopperlowe]

The newest major version of React 19 is officially stable and comes with lots of benefits and only a few breaking changes (none of which will afflict our codebase)

Benefits:

• Refs passed as props (drastically improved DX)
• improvements to Suspense and new use hook allow for better logic in client side loading states
• preparation for React compiler (currently in beta)

This upgrade should be simple since we really don't implement any associated breaking changes and they provide a codemod to fix anything that would slip through the cracks. The primary issue/blocker lies within peer-dependency issues that will require us to upgrade other packages (potentially with their own breaking changes)

I'd estimate this taking a full day to implement

[ryanhopperlowe]

Moving back to medium because this actually hasn't started yet. I think you're thinking of #836