Describe the bug

When applied IsNull filter on a dataframe's column with only null values, the filtered result is empty.

To Reproduce

I used datafusion python binding with version 27.0.0 as a simple example.

>>> import datafusion
>>> datafusion.__version__
'27.0.0'

import pandas as pd
from datafusion import functions as f

pandas_df = pd.DataFrame({"a": [None], "b": [1]})
ctx = SessionContext()
df = ctx.from_pandas(pandas_df)
df.show()

The above prints the dataframe where a's value is null:

>>> df.show()
DataFrame()
+---+---+
| a | b |
+---+---+
|   | 1 |
+---+---+

Now filter column a with is_null:

df.filter(f.col("a").is_null()).show()

The result is empty:

DataFrame()
++
++

However if there are more rows with non-null values, the filtered result is correct:

>>> pandas_df = pd.DataFrame({"a": [None, 1], "b": [1, 2]})
>>> df = ctx.from_pandas(pandas_df)
>>> df.show()
DataFrame()
+-----+---+
| a   | b |
+-----+---+
|     | 1 |
| 1.0 | 2 |
+-----+---+
>>> df.filter(f.col("a").is_null()).show()
DataFrame()
+---+---+
| a | b |
+---+---+
|   | 1 |
+---+---+

Expected behavior

The filtered result should contain the rows with null value.

Additional context

No response