fix: coder prompt & model test text (#583)

* test text fix

* Require LLM to use print() instead of logging

rdagent/components/coder/data_science/ensemble/prompts.yaml

@@ -35,6 +35,8 @@ ensemble_coder:
     {% endfor %}
     {% endif %}
 
+    You should avoid using logging module to output information in your generated code, and instead use the print() function.
+
     ## Output Format
     Please response the code in the following json format. Here is an example structure for the JSON output:
     {