[Bugfix] fix patch typo (#4351)

### What this PR does / why we need it?
Fix a bug caused by this pr:
#4223
The bug makes
vllm-ascend/vllm_ascend/patch/platform/patch_multiproc_executor.py patch
in a wrong way

### How was this patch tested?
Tested in a single node. When the environment DYNAMIC_EPLB is set to
true, the patch works correctly. When it's set to false, the patch do
not patch
- vLLM version: v0.11.0
- vLLM main:
vllm-project/vllm@2918c1b

Signed-off-by: 白永斌 <[email protected]>
Co-authored-by: 白永斌 <[email protected]>

Author: 845473182

vllm_ascend/patch/platform/__init__.py

@@ -16,12 +16,11 @@
 
 import os
 
-import vllm_ascend.envs as envs_ascend
 import vllm_ascend.patch.platform.patch_config  # noqa
 import vllm_ascend.patch.platform.patch_distributed  # noqa
 import vllm_ascend.patch.platform.patch_mamba_config  # noqa
 import vllm_ascend.patch.platform.patch_sched_yield  # noqa
 
-if envs_ascend.DYNAMIC_EPLB not in ("true", "1") or os.getenv(
+if os.getenv("DYNAMIC_EPLB", "false").lower() in ("true", "1") or os.getenv(
         "EXPERT_MAP_RECORD", "false") == "true":
     import vllm_ascend.patch.platform.patch_multiproc_executor  # noqa