date_part doesn't consider timezone

[waitingkuo]

Describe the bug

date_part doesn't work for timestamptz with non-utc timezone

To Reproduce

arrow_cast allows us to cast timestamp to timestamptz (though the behavior of arrow_cast is incorrect now #5952)

❯ select arrow_cast('2000-01-01T00:00:00'::timestamp, 'Timestamp(Nanosecond, Some("+08:00"))');
+-----------------------------+
| Utf8("2000-01-01T00:00:00") |
+-----------------------------+
| 2000-01-01T08:00:00+08:00   |
+-----------------------------+
1 row in set. Query took 0.002 seconds.

❯ select date_part('hour', arrow_cast('2000-01-01T00:00:00'::timestamp, 'Timestamp(Nanosecond, Some("+08:00"))'));
+----------------------------------------------------+
| datepart(Utf8("hour"),Utf8("2000-01-01T00:00:00")) |
+----------------------------------------------------+
| 0.0                                                |
+----------------------------------------------------+
1 row in set. Query took 0.003 seconds.

Expected behavior

should returns 8.0

Additional context

cc @tustvold will apache/arrow-rs#1936 solve this?

[tustvold]

#5952 is possibly related