Checkout Terms Block: Fix Terms and Conditions checkbox position in e…

…ditor (woocommerce#5150) (woocommerce#5191)

Within the editor, the checkbox appeared aligned at the bottom of the paragraph, while
on the front-end it would appear aligned at the top. The alignment was actually correct
but a top margin was assigned to checkboxes in the backend.

Instead of removing that globally, this commit resets it for checkboxes within the checkout
block.

assets/js/blocks/cart-checkout/checkout/inner-blocks/checkout-terms-block/editor.scss

@@ -12,6 +12,10 @@
 	}
 }
 
+.wc-block-components-checkbox {
+	margin-top: 0;
+}
+
 .wc-block-checkout__terms_notice .components-notice__action {
 	margin-left: 0;
 }