#7609994 Stats: Update Store main chart styling

Proposed Changes

• Adjust styling on the Stats Store tab page to align with the new design.
• Try to extract the same styles within the same structure from the Traffic and Store pages.

Testing Instructions

• Spin up a Jurassic Ninja site and activate the WooCommerce plugin.
• Launch the local development application.
• Navigate to the page with the JN site /store/stats/orders/week/${woo-commerce-site}.
• Ensure styling on the Store tab page is aligned with the new version of the design.
• Since the purchase flow would not be easy to simulate, modifying code locally may be easier to test.

Apply some mock data like Math.random to the value and nestedValue to make bar charts visible.

Manually replacing class names to the Delta component with is-favorable is-increase or is-unfavorable is-decrease makes the Delta display the new styles.

Pre-merge Checklist

• Have you written new tests for your changes?
• Have you tested the feature in Simple (P9HQHe-k8-p2), Atomic (P9HQHe-jW-p2), and self-hosted Jetpack sites (PCYsg-g6b-p2)?
• Have you checked for TypeScript, React or other console errors?
• Have you used memoizing on expensive computations? More info in Memoizing with create-selector and Using memoizing selectors and Our Approach to Data
• Have we added the “[Status] String Freeze” label as soon as any new strings were ready for translation (p4TIVU-5Jq-p2)?

Related to #69041