refactor: gestion des erreurs

Front-End/src/app/actions/subscriptionAction.js

@@ -17,7 +17,7 @@ const requestResponseHandler = async (response) => {
     return body;
   }
    // Throw an error with the JSON body containing the form errors
-  const error = new Error('Form submission error');
+  const error = new Error(body?.errorMessage || "Une erreur est survenue");
   error.details = body;
   throw error;
 }