Fix date formatting in system graphs

dashboard/src/components/GraphItem.vue

@@ -1,7 +1,6 @@
 
 <script setup>
 
-import moment from 'moment-timezone';
 import { onMounted, onUnmounted, useTemplateRef, watch } from 'vue';
 import Chart from 'chart.js/auto';
 import { prettyDecimalSize, formatDate } from '@cloudron/pankow/utils';
@@ -144,7 +143,7 @@ function createGraphOptions({ yscale, period, highMark }) {
           maxRotation: 0, // don't rotate the labels
           callback: function (value) {
             if (period.hours === 0) return `${5-(value-this.min)/60000}min`;
-            return moment(value).format(period.tickFormat);
+            return formatDate(period.tickFormat, value);
           },
           count, // ignored when stepSize is set
           stepSize // for realtime graph, generate steps of 1min and appropriate tick text