[Bugfix][Model] Fix Python 3.8 compatibility in Pixtral model by updating type annotations (#8490)

Author: chrisociepa

vllm/model_executor/models/pixtral.py

@@ -454,7 +454,7 @@ def forward(
         return x
 
 
-def position_meshgrid(patch_embeds_list: list[torch.Tensor], ) -> torch.Tensor:
+def position_meshgrid(patch_embeds_list: List[torch.Tensor], ) -> torch.Tensor:
     positions = torch.cat([
         torch.stack(
             torch.meshgrid(