Fix: Reference Error due to Typo in Variable Name

[Sakuk3]

Issue:

When attempting to update the cart count, a Uncaught ReferenceError: product_data is not defined error occurred.

Cause:

The error stemmed from a typo in the variable name being used.

Solution:

This pull request resolves the issue by correcting the variable name to match its intended reference.

Changes Made:

• Corrected the typo in the variable name from product_data to productData.

[duracelltomi]

Thanks for the bugfix!