Address code review feedback - simplify XSS assertion

Co-authored-by: cadtoolbox <12723486+cadtoolbox@users.noreply.github.com>

backend/tests/unit/services/test_email_service.py

@@ -159,4 +159,5 @@ class TestEmailTemplateFormatting:
 
         # Verify that script tags are escaped
         assert "<script>" in html_body
-        assert "<script>" not in html_body or html_body.count("<script>") == 0  # No unescaped script tags
+        # Verify no unescaped script tags
+        assert "<script>" not in html_body