Fix shared experts fusion + weight requant (#7177)

python/sglang/srt/models/deepseek_v2.py

@@ -1960,7 +1960,8 @@ class DeepseekV2ForCausalLM(nn.Module):
                 )
 
             if layer_id in moe_layers:
-                shared_experts = layer.mlp.shared_experts
+                shared_experts = getattr(layer.mlp, "shared_experts", None)
+                if shared_experts is not None:
                     for module in [
                         shared_experts.gate_up_proj,
                         shared_experts.down_proj,