Recurring Payments: Voiceover Cursor Focus on Payment Form

I am opening this up on behalf of a visually-impaired user who uses Apple Voiceover,

#### Steps to reproduce

1. Using a screen reader such as Apple Voiceover, navigate to and tap on the payment button created with a Recurring Payments block.
2. The credit card payment form opens up — attempt to start filling this in.

#### What I expected

I should be able to tap on the payment button, and the cursor should be focused at the top of the page so I can begin swiping right (using a screen reader) to enter fields.

#### What happened instead

The voiceover cursor is not focused on the form so it's not possible to start entering the credit card details into the form.

#### Browser / OS version

Device: iPod Touch
Browser: Safari Latest
Screen reader: Apple Voiceover

#### Screenshot / Video

https://d.pr/i/BIrmeM

#### Context / Source

#p4vt7e-6n-p2

#journey #empathy #livesharing #accessibility #painpoint #user-report

Start by reproducing the Recurring Payments block flow on an iPod Touch with Safari and Apple VoiceOver, then trace the payment button and credit card form entry points. Done means activating the payment button places the VoiceOver cursor at the beginning of the form and allows swiping through the fields to enter payment details.

Written by the indexing model from the issue text.