[diffusion] CI: fix CI script path and missing server arg in perf baseline generator (#20138)

python/sglang/multimodal_gen/test/scripts/gen_perf_baselines.py

@@ -61,6 +61,8 @@ def _build_server_extra_args(case: DiffusionTestCase) -> str:
         a += " --dit-layerwise-offload true"
     if server_args.dit_offload_prefetch_size:
         a += f" --dit-offload-prefetch-size {server_args.dit_offload_prefetch_size}"
+    if server_args.text_encoder_cpu_offload:
+        a += " --text-encoder-cpu-offload"
     if server_args.ring_degree is not None:
         a += f" --ring-degree {server_args.ring_degree}"
     if server_args.lora_path: