fix: Align to_numpy signatures

Don't need to explicitly define in `CompliantDataFrame`, as it gets it from `NumpyConvertible`

Author: dangotbanned

narwhals/_arrow/dataframe.py

@@ -508,7 +508,7 @@ def to_polars(self: Self) -> pl.DataFrame:
 
         return pl.from_arrow(self.native)  # type: ignore[return-value]
 
-    def to_numpy(self: Self) -> _2DArray:
+    def to_numpy(self: Self, dtype: Any = None, *, copy: bool | None = None) -> _2DArray:
         import numpy as np  # ignore-banned-import
 
         arr: Any = np.column_stack([col.to_numpy() for col in self.native.columns])

narwhals/_compliant/dataframe.py

@@ -156,7 +156,6 @@ def sort(
     ) -> Self: ...
     def tail(self, n: int) -> Self: ...
     def to_arrow(self) -> pa.Table: ...
-    def to_numpy(self) -> _2DArray: ...
     def to_pandas(self) -> pd.DataFrame: ...
     def to_polars(self) -> pl.DataFrame: ...
     @overload