Missing Trace implementation for S2 coordinates

[mdedenon39]

As referenced in dedalus-users (https://groups.google.com/g/dedalus-users/c/aPtmsRgx5tY), the trace operator is not implemented in S2 coordinates.

[mdedenon39]

The definitions of trace operators are localized around lines 1800 in the dedalus/core/operators.py file.
I guess it is similar to PolarTrace at l. 1829 but I don't know exactly the difference with S2coordinates in terms of spin components.
Is it just replacing cs_type ?