refactor(typing): Simplify EagerNamespace

- Only needs to be the extra stuff
- `_create_compliant_series` is removed in #2196

Author: dangotbanned

narwhals/_compliant/namespace.py

@@ -57,11 +57,8 @@ class EagerNamespace(
     CompliantNamespace[EagerDataFrameT, EagerExprT],
     Protocol[EagerDataFrameT, EagerSeriesT_co, EagerExprT],
 ):
-    @property
-    def _expr(self) -> type[EagerExprT]: ...
     @property
     def _series(self) -> type[EagerSeriesT_co]: ...
-    def all_horizontal(self, *exprs: EagerExprT) -> EagerExprT: ...
 
     @deprecated(
         "Internally used for `numpy.ndarray` -> `CompliantSeries`\n"