[SPARK-36338][PYTHON][FOLLOW-UP] Keep the original default value as 'sequence' in default index in pandas on Spark

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

This PR is a followup of https://github.com/apache/spark/pull/33570, which mistakenly changed the default value of the default index

### Why are the changes needed?

It was mistakenly changed. It was changed to check if the tests actually pass but I forgot to change it back.

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

No, it's not related yet. It fixes up the mistake of the default value mistakenly changed.
(Changed default value makes the test flaky because of the order affected by extra shuffle)

### How was this patch tested?

Manually tested.

Closes #33596 from HyukjinKwon/SPARK-36338-followup.

Authored-by: Hyukjin Kwon <gurwls223@apache.org>
Signed-off-by: Hyukjin Kwon <gurwls223@apache.org>
(cherry picked from commit 74a6b9d23b)
Signed-off-by: Hyukjin Kwon <gurwls223@apache.org>

python/pyspark/pandas/config.py

@@ -175,7 +175,7 @@ _options = [
     Option(
         key="compute.default_index_type",
         doc=("This sets the default index type: sequence, distributed and distributed-sequence."),
-        default="distributed-sequence",
+        default="sequence",
         types=str,
         check_func=(
             lambda v: v in ("sequence", "distributed", "distributed-sequence"),