Fix crash while trying to remove an approved final thesis

Caused by missing @Transactional

core/src/main/java/se/su/dsv/scipro/finalthesis/FinalThesisServiceImpl.java

@@ -134,6 +134,7 @@ public class FinalThesisServiceImpl extends AbstractServiceImpl<FinalThesis, Lon
     }
 
     @Override
+    @Transactional
     public void removeApproval(Project project) {
         setStatus(project, FinalThesis.Status.NO_DECISION);
     }