fix: handle null values in IntervalConverter and TimestampConverter

Author: Daza10samu

jooq-dialect/src/main/java/tech/ydb/jooq/binding/IntervalBinding.java

@@ -39,6 +39,9 @@ public void get(BindingGetResultSetContext<Duration> ctx) throws SQLException {
     private static class IntervalConverter implements Converter<YearToSecond, Duration> {
         @Override
         public Duration from(YearToSecond databaseObject) {
+            if (databaseObject == null) {
+                return null;
+            }
             return databaseObject.toDuration();
         }
 

jooq-dialect/src/main/java/tech/ydb/jooq/binding/TimestampBinding.java

@@ -39,6 +39,9 @@ public void get(BindingGetResultSetContext<Instant> ctx) throws SQLException {
     private static class TimestampConverter implements Converter<LocalDateTime, Instant> {
         @Override
         public Instant from(LocalDateTime databaseObject) {
+            if (databaseObject == null) {
+                return null;
+            }
             return databaseObject.toInstant(ZoneOffset.UTC);
         }