handle when lastheartbeat is undefined

Author: bernardodemarco

ui/public/locales/en.json

@@ -1523,6 +1523,7 @@
 "label.networkspeed": "Network speed",
 "label.networktype": "Network type",
 "label.networkwrite": "Network write",
+"label.never": "Never",
 "label.new": "New",
 "label.new.autoscale.vmgroup": "New AutoScaling Group",
 "label.new.instance.group": "New Instance group",

ui/src/views/infra/UsageRecords.vue

@@ -88,7 +88,7 @@
         <a-card-grid style="width: 35%; text-align: center; font-size: small;">
           <a-statistic
             :title="$t('label.lastheartbeat')"
-            :value="$toLocaleDate(serverStats.lastheartbeat)"
+            :value="serverStats.lastheartbeat ? $toLocaleDate(serverStats.lastheartbeat) : $t('label.never')"
             valueStyle="font-size: medium"
           />
           <a-card-meta :description="getTimeSince(serverStats.collectiontime)" />