[main] [bugfix] Fix misjudging quantized/unquantized scenarios (#2627)

### What this PR does / why we need it?
In a mixed-precision scenario, quant_config is not None, but MoE needs
to perform unquantized computation; however, quantized computation is
currently being used. Therefore, we put the with_quant logic into
forward, avoid misjudging in mix-precision scenarios.
### Does this PR introduce _any_ user-facing change?
no
### How was this patch tested?
e2e & ut

- vLLM version: v0.10.1.1
- vLLM main:
98ac0cb32d

Signed-off-by: Pr0Wh1teGivee <calvin_zhu0210@outlook.com>

vllm_ascend/ascend_forward_context.py

@@ -99,8 +99,6 @@ def set_ascend_forward_context(
         forward_context.fused_moe_state = fused_moe_state
         forward_context.in_profile_run = in_profile_run
 
-        with_quant = vllm_config.quant_config is not None
-        forward_context.with_quant = with_quant
         from vllm_ascend.ops.moe_dispatcher.token_dispatcher import \
             get_token_dispatcher
         dispatcher_name = get_dispatcher_name(ep_size, with_prefill)