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

* test text fix

* Require LLM to use print() instead of logging

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

@@ -336,6 +336,7 @@ data_loader_coder:
 
     ## Guidelines
     1. Ensure that the dataset is loaded strictly from `/kaggle/input/`, following the exact folder structure described in the **Data Folder Description**, and do not attempt to load data from the current directory (`./`).
+    2. 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: