Fix bug where config file from GUI could not be read correctly.

Author: RalfG

ms2rescore/config_parser.py

@@ -133,7 +133,7 @@ def parse_configurations(configurations: List[Union[dict, str, Path, Namespace]]
         else:
             raise ValueError(
                 "Configuration should be a dictionary, argparse Namespace, or path to a "
-                "configuration file."
+                f"configuration file. Got: {config.__class__.__name__}"
             )
 
     # Parse configurations

ms2rescore/gui/app.py

@@ -802,7 +802,7 @@ def function(config):
     """Function to be executed in a separate process."""
     config = config.copy()
     if config["ms2rescore"]["config_file"]:
-        config_list = [[config["ms2rescore"]["config_file"], config]]
+        config_list = [config["ms2rescore"]["config_file"], config]
     else:
         config_list = [config]
     config = parse_configurations(config_list)