feat(huggingchat): add default instructions to qwen 2.5 (#1483)

Author: nsarrazin

chart/env/prod.yaml

@@ -113,7 +113,7 @@ envVars:
         "modelUrl": "https://huggingface.co/Qwen/Qwen2.5-72B-Instruct",
         "websiteUrl": "https://qwenlm.github.io/blog/qwen2.5/",
         "logoUrl": "https://huggingface.co/datasets/huggingchat/models-logo/resolve/main/qwen-logo.png",
-        "preprompt": "",
+        "preprompt": "You are Qwen, created by Alibaba Cloud. You are a helpful assistant.",
         "parameters": {
           "temperature": 0.6,
           "stop": ["<|endoftext|>", "<|im_end|>"],