Enatega Admin Dashboard: Subcategories Disappear When Updating a Product

Describe the bug
When a user clicks on any product to update its details, the associated subcategories do not load or display in the update form. As a result, the subcategory field appears empty or missing, preventing the user from knowing or modifying the existing selection.

Steps to Reproduce:

Go to the product list page.

Click Edit on any existing product.

Observe the subcategory field.

Expected Result:
The subcategory field should display the current subcategories assigned to the product.

Actual Result:
The subcategory field is blank, and previously assigned subcategories are not shown.

Desktop (please complete the following information):

OS: [e.g. Windows]
Browser [e.g. chrome]
Version [e.g. Latest]

Labels: Enatega Multivendor Admin Dashboard, High Priority, Bug

Start at the product list page and its Edit form, then trace how an existing product's subcategories are loaded into the form. Reproduce the blank field with an assigned product and compare the loaded product data with the form's displayed value. Done means existing subcategories appear when editing a product and remain editable.

Written by the indexing model from the issue text.