platform: show any container upgrade errors in the UI

dashboard/src/components/Headerbar.vue

@@ -85,7 +85,7 @@ function onSubscriptionRequired() {
 
 const platformStatus = ref({
   message: '',
-  isReady: true,
+  state: '',
 });
 
 let platformTimeoutId = 0;
@@ -95,7 +95,7 @@ async function trackPlatformStatus() {
 
   platformStatus.value = result;
 
-  if (!result.isReady) platformTimeoutId = setTimeout(trackPlatformStatus, 5000);
+  if (result.state === 'starting') platformTimeoutId = setTimeout(trackPlatformStatus, 5000);
 }
 
 const description = marked.parse(t('support.help.description', {
@@ -158,8 +158,10 @@ onUnmounted(() => {
 
     <div style="flex-grow: 1;"></div>
 
-    <div v-if="!platformStatus.isReady" class="headerbar-info">
-      <Spinner style="margin-right: 10px"/> {{ platformStatus.message }}
+    <div v-if="platformStatus.state !== 'ready'" class="headerbar-info">
+      <i v-if="platformStatus.state === 'error'" class="fa fa-exclamation-triangle text-danger"/>
+      <Spinner v-if="platformStatus.state === 'starting'" style="margin-right: 10px"/>
+      {{ platformStatus.message }}
     </div>
 
     <!-- Warnings if subscription is expired or unpaid -->