[V0.18.0][EPLB][BugFix] Fix moe_load precision in allgather (#7890)

### What this PR does / why we need it?
Fixed the bug of incorrect reshape usage.
For example:
ori_tensor: [[1, 2, 3], [4, 5, 6]]
after reshape:
[[1, 2], [3, 4], [5, 6]]
after permute:
[[1, 4], [2, 5], [3, 6]]
Now, we will directly use squeeze for a more intuitive understanding.
pr for main:
#7887 

### Does this PR introduce _any_ user-facing change?
The actual peak-to-average ratio has successfully decreased.

Signed-off-by: shenchuxiaofugui <1311027364@qq.com>

vllm_ascend/eplb/eplb_updator.py

@@ -131,10 +131,8 @@ class EplbUpdator:
         self.update_iteration()
 
     def compute_and_set_moe_load(self):
-        local_load = self.adaptor.get_rank_expert_workload()
-        moe_load = (
-            self.comm_group.all_gather(local_load, dim=0).reshape(-1, self.world_size, *local_load.shape[1:]).cpu()
-        )
+        local_load = self.adaptor.get_rank_expert_workload().unsqueeze(1)
+        moe_load = self.comm_group.all_gather(local_load, dim=1).cpu()
 
         if self.multi_stage:
             moe_load = moe_load.permute(2, 0, 1, 3)