CRM_Core_Payment_PayPalProIPN should not call getPayPalPaymentProcessorID() if processor_id is clearly provided in URL
When processing PayPal Pro IPN messages, CRM_Core_Payment_PayPalProIPN::main()
attempts to determine the payment processor ID by calling self::getPayPalPaymentProcessorID()
(code reference), despite having already determined the processor ID xx
based on the url civicrm/payment/ipn/xx
earlier (here, then passed in here)
This method immediately logs a warning message, "Unreliable method used to get payment_processor_id for PayPal Pro IPN - this will cause problems if you have more than one instance", which seems needless if the processor_id is already provided in the url.
I propose skipping this call if processor_id is already known.