Refactor helper functions and update seeders

- Simplified `tmpostChannel` and `tmpostDefaultInventory` functions by removing caching logic.
- Changed return type of `namesWithTaxes` method in `CategoryRepository` to `mixed`.
- Enabled `ProductsTableSeeder` and added user association logic for product relations.
- Updated `BrandsSeeder` to include the product ID in the slug.
- Added `old_customer_id` to `options` in `SellersTableSeeder` for user tracking.

database/seeders/DatabaseSeeder.php

@@ -23,7 +23,7 @@ class DatabaseSeeder extends Seeder
             //    BrandsSeeder::class,
             //    CustomersTableSeeder::class,
             // SellersTableSeeder::class,
-            // ProductsTableSeeder::class,
+            ProductsTableSeeder::class,
         ]);
     }
 }