[MoE Refactor] DefaultMoERunner simplifcation (#33049)

Signed-off-by: Bill Nell <bnell@redhat.com>

vllm/model_executor/layers/fused_moe/layer.py

@@ -504,6 +504,8 @@ class FusedMoE(CustomOp):
         self.apply_router_weight_on_input = apply_router_weight_on_input
         self.activation = MoEActivation.from_str(activation)
 
+        # TODO(bnell): we should not have to create a router if the kernel is
+        # monolithic.
         self.router = create_fused_moe_router(
             top_k=top_k,
             global_num_experts=self.global_num_experts,