### What this PR does / why we need it?
This PR adds support for hierarchical communication for `dispatch_v2`
and `combine_v2` MoE operations. This is achieved by introducing a new
configuration `enable_mc2_hierarchy_comm`. When enabled, the
communication algorithm is set to "hierarchy", which support mc2 op comm
between two super pod.
The changes include:
- Adding `enable_mc2_hierarchy_comm` to `AscendConfig`.
- Modifying `TokenDispatcherWithMC2` to pass `comm_alg: "hierarchy"` to
the underlying `torch_npu` ops when the new config is enabled.
- Adding validation to ensure that this feature is only used with
compatible PTA/CANN versions and is not used with the conflicting
`fused_mc2` op.
- Updating `is_hierarchical_communication_enabled` to respect the new
configuration flag.
### Does this PR introduce _any_ user-facing change?
Yes, this PR introduces a new user-facing configuration option
`enable_mc2_hierarchy_comm` in `additional_config` to enable
hierarchical communication for MoE.
### How was this patch tested?
- vLLM version: v0.18.0
Signed-off-by: zzzzwwjj <1183291235@qq.com>
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