fix timestamp type to use microseconds instead

Author: yyanyy

spark/src/main/java/org/apache/iceberg/spark/source/StructInternalRow.java

@@ -138,7 +138,7 @@ public long getLong(int ordinal) {
     if (longVal instanceof Long) {
       return (long) longVal;
     } else if (longVal instanceof OffsetDateTime) {
-      return TimeUnit.SECONDS.toDays(((OffsetDateTime) longVal).toEpochSecond());
+      return Duration.between(Instant.EPOCH, (OffsetDateTime) longVal).toNanos() / 1000;
     } else if (longVal instanceof LocalDate) {
       return ((LocalDate) longVal).toEpochDay();
     } else {