Fix Download and Run broken by 06fefa7

Returning undefined broke the case where we already have a configuration
defined in launch.json.

Author: dlech

src/extension.ts

@@ -119,7 +119,7 @@ class Ev3devDebugConfigurationProvider implements vscode.DebugConfigurationProvi
                 };
             }
         }
-        return undefined;
+        return debugConfiguration;
     }
 }