SSR: fix graph loading indicators

frontend/src/app/components/hashrate-chart/hashrate-chart.component.html

@@ -57,7 +57,7 @@
   <div [class]="!widget ? 'chart' : 'chart-widget'" *browserOnly [style]="{ height: widget ? ((height + 20) + 'px') : null}" echarts [initOpts]="chartInitOptions" [options]="chartOptions"
     (chartInit)="onChartInit($event)">
   </div>
-  <div class="text-center loadingGraphs" *ngIf="isLoading">
+  <div class="text-center loadingGraphs" *ngIf="!stateService.isBrowser || isLoading">
     <div class="spinner-border text-light"></div>
   </div>