[SPARK-47480][PYTHON][CONNECT][TESTS] Enable doctest for `createDataF…

…rame`

### What changes were proposed in this pull request?
Enable doctest for `createDataFrame`

### Why are the changes needed?
for test coverage

536ac30 had refined the doctests, and it can be reused in connect

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

### How was this patch tested?
ci

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

Closes #45606 from zhengruifeng/enable_create_df_doc_test.

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

python/pyspark/sql/connect/session.py

@@ -968,8 +968,6 @@ def _test() -> None:
     # Spark Connect does not support to set master together.
     pyspark.sql.connect.session.SparkSession.__doc__ = None
     del pyspark.sql.connect.session.SparkSession.Builder.master.__doc__
-    # RDD API is not supported in Spark Connect.
-    del pyspark.sql.connect.session.SparkSession.createDataFrame.__doc__
 
     # TODO(SPARK-41811): Implement SparkSession.sql's string formatter
     del pyspark.sql.connect.session.SparkSession.sql.__doc__