Delete Product Metadata Item Does Not Delete From Firestore Document

[nicolasheady]

Bug report

• Extension name: firestore-stripe-payments

Describe the bug

Deleting a metadata item on a Product does not delete it from it's Firestore document.
Adding and changing metadata keys and values updates the Firestore document as expected. Adding and deleting metadata from the Price also updates the Firestore document as expected. It is only DELETING a metadata key/value pair from a Product that is not updating the corresponding document in Firestore.

To Reproduce

Steps to reproduce the behavior, please provide code snippets or a repository:

1. Go to the Product Catalog on Stripe.
2. Open a product.
3. Delete a metadata item.
4. Look at the corresponding Firestore document.

Expected behavior

Deleting an metadata item on a product should also delete it from the Firestore document.