fix(iceberg): Incorrect $partition Metadata in Trino for Iceberg Tables Written via IcebergIO.writeRows with Timestamp Partitioning (#36562)

* fix(iceberg): update month calculation to use ChronoUnit for improved accuracy

* fix(tests): update trigger file comment and modification count for IO Iceberg Integration Tests

* Update IO_Iceberg_Integration_Tests.json

---------

Co-authored-by: Mehdi DARDANI <[email protected]>
Co-authored-by: Ahmed Abualsaud <[email protected]>

Author: 3 people

.github/trigger_files/IO_Iceberg_Integration_Tests.json

@@ -1,4 +1,4 @@
 {
     "comment": "Modify this file in a trivial way to cause this test suite to run.",
-    "modification": 3
+    "modification": 4
 }

sdks/java/io/iceberg/src/main/java/org/apache/beam/sdk/io/iceberg/RecordWriterManager.java

@@ -228,8 +228,9 @@ static String getPartitionDataPath(
       String transformName =
           Preconditions.checkArgumentNotNull(partitionFieldMap.get(name)).transform().toString();
       if (Transforms.month().toString().equals(transformName)) {
-        int month = YearMonth.parse(value).getMonthValue();
-        value = String.valueOf(month);
+        long months =
+            ChronoUnit.MONTHS.between(EPOCH, YearMonth.parse(value).atDay(1).atStartOfDay());
+        value = String.valueOf(months);
       } else if (Transforms.hour().toString().equals(transformName)) {
         long hour = ChronoUnit.HOURS.between(EPOCH, LocalDateTime.parse(value, HOUR_FORMATTER));
         value = String.valueOf(hour);