chore: using anthropic.claude-3-7-sonnet-20250219-v1:0 as bedrock default model (pingcap#641)

Author: chethanuk

backend/app/rag/llms/provider.py

@@ -139,7 +139,7 @@ class LLMProviderOption(BaseModel):
         provider_display_name="Bedrock",
         provider_description="Amazon Bedrock is a fully managed foundation models service.",
         provider_url="https://docs.aws.amazon.com/bedrock/",
-        default_llm_model="anthropic.claude-3-5-sonnet-20241022-v1:0",
+        default_llm_model="anthropic.claude-3-7-sonnet-20250219-v1:0",
         llm_model_description="",
         credentials_display_name="AWS Bedrock Credentials JSON",
         credentials_description="The JSON Object of AWS Credentials, refer to https://docs.aws.amazon.com/cli/latest/userguide/cli-configure-files.html#cli-configure-files-global",