SPARK-48380: SerDeUtil.javaToPython to support batchSize parameter

[zshao9]

What changes were proposed in this pull request?

This simple PR adds a parameter batchSize to the underlying javaToPython function. This parameter is already available on pairRDDToPython.

Why are the changes needed?

With this, pyspark program can decide to use a different batch size when the default AutoBatchPickler ends up with 2GB exceeded error as in the JIRA ticket: https://issues.apache.org/jira/browse/SPARK-48380

Does this PR introduce any user-facing change?

This introduces a new way to access python RDD from python DataFrame:

# python
# The existing way to convert dataframe to RDD with auto batching (NO CHANGES)
df.rdd
# The new way to convert dataframe to RDD with batchSize of 1 (New API)
df._jdf.javaToPython(1)

How was this patch tested?

mvn test
(still testing)

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

No.

[HyukjinKwon]

Let's:

1. Create a PR against master branch
2. Add a test case
3. Fix the PR title (see also https://spark.apache.org/contributing.html)

[zshao9]

Will move to #46697