test: Add comprehensive tests for PromoComment

This commit introduces a new test suite, `PromoCommentsTestCase`, to provide robust test coverage for the promo comments API endpoints.

Key functionality covered:
- **CRUD Operations**: Full lifecycle testing for creating (POST), retrieving (GET list/detail), updating (PUT), and deleting (DELETE) comments.
- **Permissions**: Verifies that users can only modify or delete their own comments (403 Forbidden).
- **Error Handling**: Validates correct 404 Not Found responses for invalid requests, such as mismatched promo and comment IDs.
- **Data Integrity**: Ensures the `comment_count` on the parent Promo object is correctly updated after comments are created or deleted.
- **Listing & Pagination**: Confirms that comments are listed in reverse chronological order and that pagination headers (`X-Total-Count`) are accurate.

Author: RandomProgramm3r

promo_code/user/tests/user/base.py

@@ -68,8 +68,9 @@ def tearDown(self):
         business.models.Company.objects.all().delete()
         business.models.Promo.objects.all().delete()
         business.models.PromoCode.objects.all().delete()
-        user.models.User.objects.all().delete()
+        user.models.PromoComment.objects.all().delete()
         user.models.PromoLike.objects.all().delete()
+        user.models.User.objects.all().delete()
         tb_models.BlacklistedToken.objects.all().delete()
         tb_models.OutstandingToken.objects.all().delete()
         super().tearDown()