[Backport][BugFix]Fix paimon table struct type (StarRocks#30817)

Signed-off-by: leoyy0316 <571684903@qq.com>
(cherry picked from commit 23221f3)

java-extensions/paimon-reader/src/main/java/com/starrocks/paimon/reader/PaimonColumnValue.java

@@ -131,7 +131,7 @@ public void unpackStruct(List<Integer> structFieldIndex, List<ColumnValue> value
                 DataField dataField = fields.get(idx);
                 Object o = InternalRowUtils.get(array, i, dataField.type());
                 if (o != null) {
-                    cv = new PaimonColumnValue(0, dataField.type());
+                    cv = new PaimonColumnValue(o, dataField.type());
                 }
             }
             values.add(cv);