Original PR description

Issue
  
      - Install "Ecommerce" app
      - Go to 'Shop' page and edit it
      - Add a "Dynamic Products" block
      - Click on it to edit it :
      -  Select any template
      -  Select `Desks` as product category
      -  Save
      - Go to "Website -> Configuration -> eCommerce Categories"
      - Delete the "Desks" category
      - Go back to Shop page
      
      Error : "Record does not exist or has been deleted".

Cause
    
      The search domain is looking for child categories of dataset.productCategoryId
      (who does not exist anymore in the above case).
      `child_of` do a browse() to fetch the records, and therefore generate
      an error if category not found.
        
Solution
      
      Log warning message if unexptected domain and return empty records set instead.
        
opw-2440917

Forward-Port-Of: odoo/odoo#64847