make last save be in its on transaction so it can never be rolled back

Author: J0nasMayr

src/main/java/it/aboutbits/springboot/emailservice/lib/application/ManageEmail.java

@@ -139,7 +139,7 @@ Email completeClaimedSend(Email email) {
                 );
             }
         }
-        return emailRepository.save(email);
+        return transactionTemplate.execute(_ -> emailRepository.save(email));
     }
 
     void cleanupAttachments(final Email email) throws AttachmentException {