Add current product to purchase form extension points

[mak001]

It would be nicer to include the current product in the parameters passed to updatePurchaseFormFields and updateFoxyStripePurchaseFormFields.

foxystripe/src/Form/FoxyStripePurchaseForm.php

Line 223 in 6d91309

$this->extend('updatePurchaseFormFields', $fields);

foxystripe/src/Form/FoxyStripePurchaseForm.php

Line 228 in 6d91309

$this->extend('updateFoxyStripePurchaseFormFields', $fields);

[muskie9]

This can currently be accomplished via your Extension by calling $this->owner->getProduct(). That will return the product currently used by the form.