Validation for DataArray indexing

Add additional validation for `drop_sel` such that when selecting with a DataArray the dimensions must be named consistently between the DataArray and the dimension you're dropping the selection from. 

This matches the behaviour with `sel`.

Co-authored-by: Stephan Hoyer <shoyer@google.com>

Author: owena11

xarray/core/dataset.py

@@ -6082,6 +6082,12 @@ def drop_sel(
             # DataArrays are a special case where the underlying libraries don't provide
             # a good conversition.
             if isinstance(labels_for_dim, DataArray):
+                if labels_for_dim.dims not in ((), (dim,)):
+                    raise ValueError(
+                        "cannot use drop_sel() with DataArray values with "
+                        "along dimensions other than the dimensions being "
+                        f"indexed along: {labels_for_dim}"
+                   )
                 labels_for_dim = np.asarray(labels_for_dim)
             try:
                 index = self.get_index(dim)