[SPARK-50507][PYTHON][TESTS][FOLLOW-UP] Add refactored package into p…

…ure Python test

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

This PR is a followup of apache#49074 that adds refactored package into pure Python test

### Why are the changes needed?

In order to fix the pure Python build https://github.com/apache/spark/actions/runs/12215379954/job/34077255570.

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

No, test-only.

### How was this patch tested?

Will monitor the build.

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

No.

Closes apache#49106 from HyukjinKwon/SPARK-50507-followup.

Authored-by: Hyukjin Kwon <gurwls223@apache.org>
Signed-off-by: Hyukjin Kwon <gurwls223@apache.org>

python/packaging/connect/setup.py

@@ -101,6 +101,7 @@
         "pyspark.pandas.tests.connect.groupby",
         "pyspark.pandas.tests.connect.indexes",
         "pyspark.pandas.tests.connect.io",
+        "pyspark.pandas.tests.connect.pandas",
         "pyspark.pandas.tests.connect.plot",
         "pyspark.pandas.tests.connect.resample",
         "pyspark.pandas.tests.connect.reshape",