Fix broken management of alert messages

In aded591, the function to add alert message has been modified
for no good reason resulting in message to be empty in the interface.

We also fix alert message management when loading data. This has been
missed when switching to VueJS. We shouldn't use "this" keyword anymore in
vue components or views.

powa/static/js/App.vue

@@ -165,7 +165,7 @@ import LoginView from "@/components/LoginView.vue";
 import { encodeQueryData } from "@/utils/query";
 import { useMessageService } from "@/composables/MessageService.js";
 
-const { alertMessages, addAlertMessage, removeAlertMessage } =
+const { alertMessages, addAlertMessage, addAlertMessages, removeAlertMessage } =
   useMessageService();
 
 const theme = useTheme();
@@ -355,7 +355,7 @@ function loadData() {
       try {
         const data = JSON.parse(response);
         if (data) {
-          this.addAlertMessages(data.messages);
+          addAlertMessages(data.messages);
         }
       } catch (error) {
         // pass

powa/static/js/composables/MessageService.js

@@ -27,8 +27,10 @@ function addAlertMessage(level, message) {
 }
 
 function addAlertMessages(messages) {
-  for (let message in messages) {
-    addAlertMessage(message.level, message.message);
+  for (let level in messages) {
+    for (let message of messages[level]) {
+      addAlertMessage(level, message);
+    }
   }
 }
 function removeAlertMessage(id) {