#4312857 Show premium price for premium domain suggestions when there is free plan credit

Changes proposed in this Pull Request

• We need to show the premium price for premium domain suggestions when there is free plan credit because premium domains shouldn’t bundle with plans
• Also show “Premium” label in the checkout cart too

Here’s how the cart and the checkout look:

Testing instructions

• Apply D48644-code on your sandbox
• On site with plan and unused domain credit (or just add plan to your cart first)
• Search for premium domain like anna or dale (you should use the sandboxed public-api)
• Verify that the domain premium price is shown instead of “free with your plan” that is displayed for regular priced domains
• Check the cart items and if there is Premium in there
• Click on Checkout and verify that the domain is marked as Premium in there too