chores: update default model

.env

@@ -79,21 +79,8 @@ TEXT_EMBEDDING_MODELS = `[
 # 'name', 'userMessageToken', 'assistantMessageToken' are required
 MODELS=`[
     {
-      "name": "mistralai/Mistral-7B-Instruct-v0.1",
-      "displayName": "mistralai/Mistral-7B-Instruct-v0.1",
-      "description": "Mistral 7B is a new Apache 2.0 model, released by Mistral AI that outperforms Llama2 13B in benchmarks.",
-      "websiteUrl": "https://mistral.ai/news/announcing-mistral-7b/",
-      "preprompt": "",
-      "chatPromptTemplate" : "<s>{{#each messages}}{{#ifUser}}[INST] {{#if @first}}{{#if @root.preprompt}}{{@root.preprompt}}\n{{/if}}{{/if}}{{content}} [/INST]{{/ifUser}}{{#ifAssistant}}{{content}}</s>{{/ifAssistant}}{{/each}}",
-      "parameters": {
-        "temperature": 0.1,
-        "top_p": 0.95,
-        "repetition_penalty": 1.2,
-        "top_k": 50,
-        "truncate": 3072,
-        "max_new_tokens": 1024,
-        "stop": ["</s>"]
-      },
+      "name": "HuggingFaceTB/SmolLM2-1.7B-Instruct",
+      "description": "SmolLM2-1.7B is the latest lightweight model from the Hugging Face TB Research team.",
       "promptExamples": [
         {
           "title": "Write an email from bullet list",