remove duplicated example code (#10884)

Author: jmeischner

xarray/core/common.py

@@ -1203,14 +1203,6 @@ def where(self, cond: Any, other: Any = dtypes.NA, drop: bool = False) -> Self:
                [-20, -21, -22, -23, -24]])
         Dimensions without coordinates: x, y
 
-        >>> a.where(a.x + a.y < 4, drop=True)
-        <xarray.DataArray (x: 4, y: 4)> Size: 128B
-        array([[ 0.,  1.,  2.,  3.],
-               [ 5.,  6.,  7., nan],
-               [10., 11., nan, nan],
-               [15., nan, nan, nan]])
-        Dimensions without coordinates: x, y
-
         See Also
         --------
         numpy.where : corresponding numpy function