REDMINE_ISSUE-11908

add status 204 to error detection in project_mapping and remove empty container for messages in App.vue

src/store/index.js

@@ -92,7 +92,7 @@ export default new Vuex.Store({
     },
     DISPLAY_MESSAGE(state, comment) {
       state.messages = [{ comment }, ...state.messages];
-      document.getElementById("messages").scrollIntoView({ block: "start", inline: "nearest" });
+      document.getElementById("content").scrollIntoView({ block: "start", inline: "nearest" });
     },
     CLEAR_MESSAGES(state) {
       state.messages = [];