[EPLB]Record expert map without dynamic eplb. (#3409)

What this PR does / why we need it?
1.Record expert map without dynamic eplb.
2.Add export PYTHONOPTIMIZE=1  when using dynamic eplb.
3.change eplb doc

Does this PR introduce any user-facing change?
How was this patch tested?
Qwen3_moe in A3.

- vLLM version: v0.11.0

---------

Signed-off-by: offline0806 <3337230449@qq.com>
Co-authored-by: offline0806 <3337230449@qq.com>

vllm_ascend/eplb/eplb_updator.py

@@ -137,7 +137,8 @@ class EplbUpdator:
             self.compute_and_set_moe_load(is_clear=True)
             self.wakeup_eplb_worker()
 
-        if self.update_expert_weight_flag():
+        if self.update_expert_weight_flag(
+        ) and self.expert_map_record_path is None:
             self.eplb_loader.update_expert_map_and_weight(self.reqs)
 
         self.update_iteration()