Drop special handling of min_periods for Rolling.count (#13483)

This PR drops a special handling for `Rolling.count` where we always default to `min_periods=0`, this is an inconsistency that pandas-2.0 resolves in: pandas-dev/pandas#48839

This PR fixes 2 pytest failures:
```
= 229 failed, 95769 passed, 2045 skipped, 764 xfailed, 300 xpassed in 458.04s (0:07:38) =
```
On `pandas_2.0_feature_branch`:
```
= 231 failed, 95767 passed, 2045 skipped, 764 xfailed, 300 xpassed in 457.58s (0:07:37) =
```

Author: galipremsagar

python/cudf/cudf/core/window/rolling.py

@@ -543,8 +543,6 @@ def _window_to_window_sizes(self, window):
             )
 
     def _apply_agg(self, agg_name):
-        if agg_name == "count" and not self._time_window:
-            self.min_periods = 0
         index = cudf.MultiIndex.from_frame(
             cudf.DataFrame(
                 {

python/cudf/cudf/tests/test_rolling.py

@@ -8,14 +8,14 @@
 import pytest
 
 import cudf
-from cudf.core._compat import PANDAS_GE_150, PANDAS_LT_140
+from cudf.core._compat import PANDAS_GE_150, PANDAS_LT_140, PANDAS_GE_200
 from cudf.testing._utils import _create_pandas_series, assert_eq
 from cudf.testing.dataset_generator import rand_dataframe
 
 
 @contextmanager
 def _hide_pandas_rolling_min_periods_warning(agg):
-    if agg == "count":
+    if not PANDAS_GE_200 and agg == "count":
         with pytest.warns(
             FutureWarning,
             match="min_periods=None will default to the size of window "