Event register orange Paypal Button with Paypal Pro results in form validation jquery error

Reproduce by:

1. setting up Paypal Pro processor
2. go to civicrm/event/register clicking the orange button should send you to Paypay.com to login instead of paying by card
3. instead it immediately triggers the jquery form validation required fields for card

This issue was resolved for Contribution pages already but persists for Event Registration #147 (closed)

added regression label

changed milestone to %5.30.0

https://github.com/civicrm/civicrm-core/pull/18680

closed

mentioned in commit core@5c0576a3

mentioned in commit core@ca748f0d

The javascript errors are fixed but we have been able to reproduce other errors related to the reCaptcha system at Paypal.com. I am not sure if these can be fixed on CiviCRM's side or not but we should be aware of the following experience from user testing.

In Chrome and Safari the Javascript errors are fixed -- when you click the Paypal button, there's no validation error requiring the user to input CC fields.

But, when I go to Paypal, I'm asked to complete a ReCaptcha at this URL: https://www.paypal.com//cgi-bin/webscr?cmd=_express-checkout&token=EC-2JE64037K02097038. Once I complete the challenge, the page does not reload to the log-in screen. Instead it just sits with the challenge results accepted. If I then reload the page, it redirects me to the Paypal log-in page as it should at this URL: https://www.paypal.com//cgi-bin/webscr?cmd=_express-checkout&token=EC-2JE64037K02097038

In Firefox, the Javascript errors are fixed -- when I click the Paypal button, there's no validation error requiring the user to input CC fields. When you go to Paypal, I'm asked to complete a ReCaptcha. Once I complete the challenge, the Paypal experience is different page loads the sad dinosaur error screen "hmm we're having trouble finding that site"

@Stoob probably worth it's own issue

mentioned in issue #153