[iceberg] Fix missing parent snapshot id in createMetadataWithoutBase (#8305)

Author: weibangpeng

paimon-core/src/main/java/org/apache/paimon/iceberg/IcebergCommitCallback.java

@@ -395,7 +395,7 @@ private void createMetadataWithoutBase(long snapshotId) throws IOException {
                 new IcebergSnapshot(
                         snapshotId,
                         snapshotId,
-                        null,
+                        snapshotId == Snapshot.FIRST_SNAPSHOT_ID ? null : (Long) (snapshotId - 1),
                         System.currentTimeMillis(),
                         snapshotSummary,
                         pathFactory.toManifestListPath(manifestListFileName).toString(),