[feat] support dispatch_v2/combine_v2 hierarchy communication (#7698)

### 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>

vllm_ascend/utils.py

@@ -991,7 +991,9 @@ def calculate_dp_buffer_size() -> int:
 # and HCCL_INTRA_ROCE_ENABLE=0 can reduce cross-machine communication traffic and
 # significantly improve communication performance of MC2 ops dispatch/combine.
 def is_hierarchical_communication_enabled():
-    return os.getenv("HCCL_INTRA_ROCE_ENABLE", "") == "0" and os.getenv("HCCL_INTRA_PCIE_ENABLE", "") == "1"
+    return (
+        os.getenv("HCCL_INTRA_ROCE_ENABLE", "") == "0" and os.getenv("HCCL_INTRA_PCIE_ENABLE", "") == "1"
+    ) or get_ascend_config().enable_mc2_hierarchy_comm
 
 
 def has_layer_idx(model_instance: torch.nn.Module) -> bool: