Show UPE element on block editor

[Mayisha]

In block editor, the stripe payment elements fail to render because of getStripeServerData function not returning any data.

Changes proposed in this Pull Request:

• In block checkout, the stripe data is present in 'stripe_data' on both frontend and editor. So getting the data from this attribute.

Testing instructions

• Enable the card payment method on Stripe settings page.
• Go to the block checkout editor and open the browser console.
• In develop, notice an error in the console and the card payment element is empty.

• In this branch notice that the console error is gone. And the card element is present.