Pay by link - Capturing order from guest user causing fatal error when Vaulting is enabled (3326)

[Dinamiko]

A fatal error "call to a member function authorizations() on null" is thrown when trying to capture authorized payment from guest user.

Steps to reproduce

• Set intent to Authorize
• Enable Vaulting
• Create manual order for guest user
• Pay for this order
• Capture this order
  • Observe error

Possible cause

It is currently possible to create a PurchaseUnit instance with a null Payments value. The consumer code is calling payment authorizations on a null payments instance and therefore the error "call to a member function authorizations() on null" is thrown.

Proposed solution

Ensure purchase units payments instance is not null before using it.