Update my_openai_api.py 忽略客户端传来的未知字段

像dify这样的客户端，会传入一个用户序列号, 需要兼容一下,避免报错.
```
request.json={'model': 'minimind-small-T', 'stream': True, 'temperature': 0.7, 'messages': [{'role': 'user', 'content': '1'}], 'user': 'cdc1f28b-4bb3-4326-ac4b-1cf78e0a6a3b'}
```

my_openai_api.py

@@ -14,7 +14,7 @@ from flask_cors import CORS
 from sentence_transformers import SentenceTransformer
 from sklearn.preprocessing import PolynomialFeatures
 from transformers import AutoTokenizer, AutoModelForCausalLM
-from marshmallow import validate, Schema, fields
+from marshmallow import validate, Schema, fields, EXCLUDE
 from pydantic import BaseModel
 
 warnings.filterwarnings('ignore', category=UserWarning)
@@ -165,6 +165,9 @@ class ChatMessageSchema(Schema):
 
 
 class CreateChatCompletionSchema(Schema):
+    class Meta:
+        unknown = EXCLUDE  # 忽略未知的字段
+
     model = fields.Str(required=True, metadata={"example": "minimind"})
     messages = fields.List(
         fields.Nested(ChatMessageSchema), required=True,