### What this PR does / why we need it?
fix https://github.com/vllm-project/vllm-ascend/issues/2702
- A2: skip graph_size update that makes it to tp_size because
dispatch/combine op support different batch size across EP ranks
- A3: add `max_num_reqs = max(new_graph_batch_sizes)` to fix graph_size
and max_num_reqs mismatch
### Does this PR introduce _any_ user-facing change?
Nope
### How was this patch tested?
- vLLM version: v0.10.1.1
- vLLM main:
e599e2c65e
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Signed-off-by: realliujiaxu <realliujiaxu@163.com>