[feat]decode convert bsnd to tnd and fix bug when pcp and dcp (#3980)

### What this PR does / why we need it?
1、in attention_v1 module, convert bsnd t0 tnd when pcp and dcp
2、fix tochair bug: service startup problem

### Does this PR introduce _any_ user-facing change?

### How was this patch tested?

- vLLM version: v0.11.0
- vLLM main:
83f478bb19

Signed-off-by: weiguihua2 <weiguihua2@huawei.com>

vllm_ascend/attention/mla_v1.py

@@ -140,8 +140,7 @@ class AscendMLADecodeMetadata:
     attn_mask: Optional[torch.Tensor] = None
     sin: torch.Tensor = None
     cos: torch.Tensor = None
-    num_computed_tokens_of_pcp_dcp: Optional[list[Optional[list[Optional[
-        list[int]]]]]] = None
+    num_computed_tokens_of_pcp_dcp: Optional[list[list[list[int]]]] = None
     seq_mask_pcp: torch.Tensor = None
     seq_mask_dcp: torch.Tensor = None
     cp_seq_len: torch.Tensor = None