feat: debounce quantity form per cart line item

[matthewvolk]

What/Why?

The updateLineItem server action can be spammed pretty easily due to the fact that we are optimistically updating the cart line items in response to increment, decrement, and delete actions. Quantity updates were a good candidate for debouncing, which is exactly what this PR adds. With that said, this PR does not fix the fact that users can still spam delete actions on line items. That will need to be a fix for another PR.

Important

This PR changes the CounterForm component pretty drastically. For one, it removes the HTML <form> entirely. When reviewing this PR, we should weigh the impact of decisions like that, I'd be interested in hearing everyone's thoughts.

Fixes #2476

Testing

1. Navigate to Preview URL
2. Add a product to cart
3. Navigate to Cart
4. Open network panel
5. Rapidly increase the quantity of a cart line item by 10
6. Notice only one POST request to /cart is logged in the network panel.

Migration

🚧 TODO

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Latest commit: 3d86732

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