Change button state after notification signup

We would like the product page button to update after a customer has already completed the notification signup form. Since the form can include email and/or phone number fields, the button should no longer prompt the customer to sign up again and instead show a clear confirmation state, such as a message indicating they will be notified when the product is available.

This would reduce confusion, prevent duplicate signups, and make it clearer to customers that their notification request was successfully submitted.

If this would be helpful for your store as well, please upvote this request!