Improve error diagnostics for search_central_via_connection when search_path is None (#708)

* Initial plan

* Move display_search_path into if block with rclone remote name for None case

Co-authored-by: JoeZiminski <55797454+JoeZiminski@users.noreply.github.com>

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: JoeZiminski <55797454+JoeZiminski@users.noreply.github.com>

Author: Copilot

datashuttle/utils/folders.py

@@ -718,8 +718,13 @@ def search_central_via_connection(
     all_filenames: list = []
 
     if output.returncode != 0:
+        display_search_path = (
+            f"{rclone_config_name}:<root>"
+            if search_path is None
+            else final_search_path
+        )
         utils.log_and_message(
-            f"Error searching files at {final_search_path}\n"
+            f"Error searching files at {display_search_path}\n"
             f"{output.stderr.decode('utf-8') if output.stderr else ''}"
         )
         return all_folder_names, all_filenames