[SPARK-41872][CONNECT][PYTHON][TESTS] Enable tests test_fillna and …

…`test_replace`

### What changes were proposed in this pull request?
Enable `test_fillna` and `test_replace`

### Why are the changes needed?
test coverage

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

### How was this patch tested?
enabled tests

Closes apache#39477 from zhengruifeng/connect_fix_41872.

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

python/pyspark/sql/tests/connect/test_parity_dataframe.py

@@ -62,11 +62,6 @@ def test_duplicated_column_names(self):
     def test_extended_hint_types(self):
         super().test_extended_hint_types()
 
-    # TODO(SPARK-41872): Fix DataFrame createDataframe handling of None
-    @unittest.skip("Fails in Spark Connect, should enable.")
-    def test_fillna(self):
-        super().test_fillna()
-
     # TODO: comparing types, need to expose connect types
     @unittest.skip("Fails in Spark Connect, should enable.")
     def test_generic_hints(self):
@@ -105,11 +100,6 @@ def test_pandas_api(self):
     def test_repartitionByRange_dataframe(self):
         super().test_repartitionByRange_dataframe()
 
-    # TODO(SPARK-41872): Fix DataFrame createDataframe handling of None
-    @unittest.skip("Fails in Spark Connect, should enable.")
-    def test_replace(self):
-        super().test_replace()
-
     # TODO(SPARK-41834): Implement SparkSession.conf
     @unittest.skip("Fails in Spark Connect, should enable.")
     def test_repr_behaviors(self):