feat(router.py): enable settting 'order' for a deployment in model list

Allows user to control which model gets called first in model group

litellm/utils.py

@@ -6196,6 +6196,27 @@ def calculate_max_parallel_requests(
     return None
 
 
+def _get_order_filtered_deployments(healthy_deployments: List[Dict]) -> List:
+    min_order = min(
+        (
+            deployment["litellm_params"]["order"]
+            for deployment in healthy_deployments
+            if "order" in deployment["litellm_params"]
+        ),
+        default=None,
+    )
+
+    if min_order is not None:
+        filtered_deployments = [
+            deployment
+            for deployment in healthy_deployments
+            if deployment["litellm_params"].get("order") == min_order
+        ]
+
+        return filtered_deployments
+    return healthy_deployments
+
+
 def _get_model_region(
     custom_llm_provider: str, litellm_params: LiteLLM_Params
 ) -> Optional[str]: