[SPARK-54123][PYTHON] Add timezone to make the timestamp an absolute time

### What changes were proposed in this pull request?

Adds timezone to make the timestamp in the log record JSON string the absolute time.

### Why are the changes needed?

Without the timezone, the timestamp of each log record doesn't reflect the session timezone, which makes it confusing.

<details>
<summary>example</summary>

```python
>>> from pyspark.sql.functions import *
>>> import logging
>>>
>>> udf
... def logging_test_udf(x):
...     logger = logging.getLogger("test")
...     logger.warning(f"message")
...     return str(x)
...
>>>
>>> spark.conf.set("spark.sql.pyspark.worker.logging.enabled", True)
>>>
>>> spark.range(1).select(logging_test_udf("id")).show()
...
```

</details>

- Before

```python
>>> spark.conf.get('spark.sql.session.timeZone')
'America/Los_Angeles'
>>> spark.sql("select ts from system.session.python_worker_logs").show(truncate=False)
+--------------------------+
|ts                        |
+--------------------------+
|2025-10-31 17:17:59.495541|
+--------------------------+

>>> spark.conf.set('spark.sql.session.timeZone', 'UTC')
>>> spark.sql("select ts from system.session.python_worker_logs").show(truncate=False)
+--------------------------+
|ts                        |
+--------------------------+
|2025-10-31 17:17:59.495541|
+--------------------------+
```

- After

```python
>>> spark.conf.get('spark.sql.session.timeZone')
'America/Los_Angeles'
>>> spark.sql("select ts from system.session.python_worker_logs").show(truncate=False)
+--------------------------+
|ts                        |
+--------------------------+
|2025-10-31 17:19:52.152868|
+--------------------------+

>>> spark.conf.set('spark.sql.session.timeZone', 'UTC')
>>> spark.sql("select ts from system.session.python_worker_logs").show(truncate=False)
+--------------------------+
|ts                        |
+--------------------------+
|2025-11-01 00:19:52.152868|
+--------------------------+
```

### Does this PR introduce _any_ user-facing change?

Yes, the timestamp of log record is now absolute time.

### How was this patch tested?

Manually.

### Was this patch authored or co-authored using generative AI tooling?

No.

Closes #52823 from ueshin/issues/SPARK-54123/timezone.

Authored-by: Takuya Ueshin <[email protected]>
Signed-off-by: Hyukjin Kwon <[email protected]>

Author: ueshin

python/pyspark/logger/worker_io.py

@@ -164,6 +164,7 @@ def formatTime(self, record: logging.LogRecord, datefmt: Optional[str] = None) -
                 )
             elif self.default_msec_format:
                 s = self.default_msec_format % (s, record.msecs)
+            s = f"{s}{time.strftime('%z', ct)}"
         return s