Missing ETP Support in mca_adapter Under Expert Parallelism

Could we consider adding support for Megatron-MoE's ETP (Expert-Tensor Parallel) sharding?
Right now, when initializing expert-parallel in MoE, it inherits the non-MoE tensor-parallel group by default.

Start at the mca_adapter expert-parallel initialization described in the issue and trace how the non-MoE tensor-parallel group is selected. Determine the expected Megatron-MoE ETP sharding behavior and define tests that distinguish the ETP group from the inherited tensor-parallel group; done means ETP initialization uses the correct sharding.

Written by the indexing model from the issue text.