[Bugfix] Fix padding logic in eagle proposer for kimi25 (#7348)

### What this PR does / why we need it?
This PR aims to fix padding logic in eagle proposer for kimi25. Main
changes involve:
1. modify the way to obtain draft model attention builder and backend
2. add block table padding & related tensor slicing in common metadata
when `draft_step>1` for solving fia verifying error
3. replace block table in `update_graph_params` for solving fia
verifying error

- vLLM version: v0.17.0
- vLLM main:
4034c3d32e

Signed-off-by: Zetong Li <slippersss@126.com>

vllm_ascend/worker/model_runner_v1.py

@@ -215,6 +215,7 @@ class ExecuteModelState(NamedTuple):
     positions: torch.Tensor
     ec_connector_output: "ECConnectorOutput | None"
     cudagraph_stats: CUDAGraphStat | None
+    batch_desc: BatchDescriptor
 
 
 class NPUModelRunner(GPUModelRunner):
@@ -995,6 +996,7 @@ class NPUModelRunner(GPUModelRunner):
         hidden_states: torch.Tensor,
         aux_hidden_states: torch.Tensor = None,
         sample_hidden_states: torch.Tensor = None,
+        target_model_batch_desc: BatchDescriptor = None,
     ) -> list[list[int]] | None:
         if not self.drafter:
             # Speculative decoding is not enabled.
@@ -1115,6 +1117,7 @@ class NPUModelRunner(GPUModelRunner):
                 next_token_ids=next_token_ids,
                 token_indices_to_sample=token_indices_to_sample,
                 common_attn_metadata=common_attn_metadata,
+                target_model_batch_desc=target_model_batch_desc,
                 sampling_metadata=sampling_metadata,
                 req_scheduled_tokens=req_scheduled_tokens,
                 long_seq_metadata=long_seq_metadata,
@@ -1455,6 +1458,7 @@ class NPUModelRunner(GPUModelRunner):
                 positions,
                 ec_connector_output,
                 cudagraph_stats,
+                batch_desc,
             )
             self.kv_connector_output = kv_connector_output
         return None
@@ -1497,6 +1501,7 @@ class NPUModelRunner(GPUModelRunner):
             positions,
             ec_connector_output,
             cudagraph_stats,
+            batch_desc,
         ) = self.execute_model_state
         # Clear ephemeral state.
         self.execute_model_state = None
@@ -1533,6 +1538,7 @@ class NPUModelRunner(GPUModelRunner):
                 hidden_states,
                 aux_hidden_states,
                 sample_hidden_states,
+                batch_desc,
             )
             self._copy_draft_token_ids_to_cpu(scheduler_output)