€ 0,00 refund triggered on deleting payments

It seems that deleting payments can trigger refunds of € 0,00:

This seems to be caused by operands of incompatible types (float vs string):

wp-pronamic-pay-woocommerce/src/Extension.php

Lines 762 to 769 in 64fe6c9

    
           $wc_refunded_amount = (float) $order->get_meta( '_pronamic_amount_refunded', true ); 
        
           $refunded_value = $refunded_amount->get_value(); 
        
           if ( $wc_refunded_amount === $refunded_value ) { 
        
           	return; 
        
           }

Internal Help Scout ticket: https://secure.helpscout.net/conversation/2077581202/24843/

@remcotolsma I propose the below change, but find it a bit strange to first cast the meta to float and then to string — only to end up with string 0 instead of an empty string if there is no _pronamic_amount_refunded order meta. Any other ideas? Money and Number classes do not have a to_float() method, otherwise we could maybe use that?

 if ( (string) $wc_refunded_amount === $refunded_value ) {

Should we introduce a equals method in the Number and/or Money class?
https://github.com/pronamic/wp-number/blob/c26538f223ae4326e8758679ed7372020d15b1d1/src/Number.php

A bit like:
https://github.com/moneyphp/money/blob/43580b8a94142ae5db9e4c86c6ecaabea66f27c9/src/Money.php#L109-L127

And/or we should not create a refund if $amount_difference is zero?
https://github.com/pronamic/wp-number/blob/c26538f223ae4326e8758679ed7372020d15b1d1/src/Number.php#L186-L196

Discussed with @remcotolsma at Pronamic HQ and resolved in 2ed4a20.

	$wc_refunded_amount = (float) $order->get_meta( '_pronamic_amount_refunded', true );

	$refunded_value = $refunded_amount->get_value();

	if ( $wc_refunded_amount === $refunded_value ) {
	return;
	}