[DP][V1] Fix rank set in DP scenario & Bump torch-npu version to 2.5.1.post1.dev20250528 (#1235)

### What this PR does / why we need it?
1. Fix rank set in DP scenario. The new poc version of torch-npu support
setting `ASCEND_RT_VISIBLE_DEVICES` dynamically, thus we could use the
rank set in `DPEngineCoreProc` directly instead of calculating local
rank across dp by hand in the patched `_init_data_parallel`

Closes: https://github.com/vllm-project/vllm-ascend/issues/1170

2. Bump torch-npu version to 2.5.1.post1.dev20250528

Closes: https://github.com/vllm-project/vllm-ascend/pull/1242
Closes: https://github.com/vllm-project/vllm-ascend/issues/1232


### How was this patch tested?
CI passed with new added test.

---------

Signed-off-by: MengqingCao <cmq0113@163.com>
Signed-off-by: Icey <1790571317@qq.com>
Co-authored-by: Icey <1790571317@qq.com>

requirements.txt

@@ -10,7 +10,6 @@ pyyaml
 scipy
 setuptools>=64
 setuptools-scm>=8
-torch-npu==2.5.1
 torch>=2.5.1
 torchvision<0.21.0
 wheel
@@ -21,3 +20,8 @@ quart
 
 # Required for N-gram speculative decoding
 numba
+
+# Install torch_npu
+--pre
+--extra-index-url https://mirrors.huaweicloud.com/ascend/repos/pypi
+torch-npu==2.5.1.post1.dev20250528