Fix GraphQL request for PR body (#479)

Author: stanislav-tkach

utilities/project-fields-validator/main.py

@@ -264,6 +264,7 @@ def get_pr_details(self, org_name: str, repo_name: str, pr_number: int) -> dict[
                   login
                 }
               }
+              body
             }
           }
         }