Graphs loading indicators update

frontend/src/app/components/block-fees-graph/block-fees-graph.component.html

@@ -37,7 +37,7 @@
   </div>
 
   <div class="chart" *browserOnly echarts [initOpts]="chartInitOptions" [options]="chartOptions"
-    (chartInit)="onChartInit($event)">
+    (chartInit)="onChartInit($event)" [style]="{opacity: isLoading ? 0.5 : 1}">
   </div>
   <div class="text-center loadingGraphs" *ngIf="!stateService.isBrowser || isLoading">
     <div class="spinner-border text-light"></div>