REF: remove GeoDataFrame shim in _constructor_from_mgr (#65175)

Author: jbrockmendel

pandas/core/frame.py

@@ -425,11 +425,6 @@ def _constructor_from_mgr(self, mgr, axes) -> DataFrame:
             #  this check is slightly faster, benefiting the most-common case.
             return df
 
-        elif type(self).__name__ == "GeoDataFrame":
-            # Shim until geopandas can override their _constructor_from_mgr
-            #  bc they have different behavior for Managers than for DataFrames
-            return self._constructor(mgr)
-
         # We assume that the subclass __init__ knows how to handle a
         #  pd.DataFrame object.
         return self._constructor(df)