add TODO

Author: HonahX

extension/persistence/eclipselink/src/main/java/org/apache/polaris/extension/persistence/impl/eclipselink/PolarisEclipseLinkStore.java

@@ -420,6 +420,7 @@ void writeToPolicyMappingRecords(
     diagnosticServices.check(session != null, "session_is_null");
     checkInitialized();
 
+    // TODO: combine existence check and write into one statement
     ModelPolicyMappingRecord model =
         lookupPolicyMappingRecord(
             session,