refactor: extend KnowledgeModelSerializer fields to include file size and count limits

--bug=1057593 --user=刘瑞斌 【共享资源】共享知识库设置界面，向量模型为空，不回显 https://www.tapd.cn/62980211/s/1720862

Author: liuruibin

apps/knowledge/serializers/knowledge.py

@@ -49,7 +49,8 @@
 class KnowledgeModelSerializer(serializers.ModelSerializer):
     class Meta:
         model = Knowledge
-        fields = ['id', 'name', 'desc', 'meta', 'folder_id', 'type', 'workspace_id', 'create_time', 'update_time']
+        fields = ['id', 'name', 'desc', 'meta', 'folder_id', 'type', 'workspace_id', 'create_time',
+                  'update_time', 'file_size_limit', 'file_count_limit', 'embedding_model_id']
 
 
 class KnowledgeBaseCreateRequest(serializers.Serializer):