[SPARK-54882][PYTHON] Remove legacy PYARROW_IGNORE_TIMEZONE

### What changes were proposed in this pull request?
Remove legacy PYARROW_IGNORE_TIMEZONE

### Why are the changes needed?
it was added in spark 3.0 for integration with pyarrow 2.0 5e33155

seems it is no longer needed for pyspark tests

### Does this PR introduce _any_ user-facing change?
no

### How was this patch tested?
ci

### Was this patch authored or co-authored using generative AI tooling?
no

Closes #53660 from zhengruifeng/test_without_PYARROW_IGNORE_TIMEZONE.

Authored-by: Ruifeng Zheng <[email protected]>
Signed-off-by: Ruifeng Zheng <[email protected]>

Author: zhengruifeng

binder/postBuild

@@ -39,9 +39,6 @@ fi
 
 pip install plotly "pandas<2.0.0" "pyspark[sql,ml,mllib,pandas_on_spark,connect]$SPECIFIER$VERSION"
 
-# Set 'PYARROW_IGNORE_TIMEZONE' to suppress warnings from PyArrow.
-echo "export PYARROW_IGNORE_TIMEZONE=1" >> ~/.profile
-
 # Add sbin to PATH to run `start-connect-server.sh`.
 SPARK_HOME=$(python -c "from pyspark.find_spark_home import _find_spark_home; print(_find_spark_home())")
 echo "export PATH=${PATH}:${SPARK_HOME}/sbin" >> ~/.profile

python/pyspark/pandas/__init__.py

@@ -39,16 +39,6 @@
     else:
         raise
 
-if "PYARROW_IGNORE_TIMEZONE" not in os.environ:
-    warnings.warn(
-        "'PYARROW_IGNORE_TIMEZONE' environment variable was not set. It is required to "
-        "set this environment variable to '1' in both driver and executor sides if you use "
-        "pyarrow>=2.0.0. "
-        "pandas-on-Spark will set it for you but it does not work if there is a Spark context "
-        "already launched."
-    )
-    os.environ["PYARROW_IGNORE_TIMEZONE"] = "1"
-
 from pyspark.pandas.frame import DataFrame
 from pyspark.pandas.indexes.base import Index
 from pyspark.pandas.indexes.category import CategoricalIndex

python/run-tests.py

@@ -196,8 +196,6 @@ def run_individual_python_test(target_dir, test_name, pyspark_python, keep_test_
         'SPARK_PREPEND_CLASSES': '1',
         'PYSPARK_PYTHON': which(pyspark_python),
         'PYSPARK_DRIVER_PYTHON': which(pyspark_python),
-        # Preserve legacy nested timezone behavior for pyarrow>=2, remove after SPARK-32285
-        'PYARROW_IGNORE_TIMEZONE': '1',
     })
 
     if "SPARK_CONNECT_TESTING_REMOTE" in os.environ: