Tiny assert EPLB is used together with expert parallel (#8381)

python/sglang/srt/server_args.py

@@ -458,6 +458,9 @@ class ServerArgs:
                 "EPLB is enabled or init_expert_location is provided. ep_dispatch_algorithm is configured."
             )
 
+        if self.enable_eplb:
+            assert self.enable_ep_moe or self.enable_deepep_moe
+
         if self.enable_expert_distribution_metrics and (
             self.expert_distribution_recorder_mode is None
         ):