chore(checkout): Clean up some styling

[isabellaenriquez]

In /amCheckout/:

• Removes all uses of deprecated space function
• Replaces uses of custom styled components with scraps

[ramintaghizada]

please structure your code

[getsantry]

This issue has gone three weeks without activity. In another week, I will close it.

But! If you comment or otherwise update it, I will reset the clock, and if you remove the label Waiting for: Community, I will leave it alone ... forever!

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"A weed is but an unloved flower." ― Ella Wheeler Wilcox 🥀