Fix double http query when switching timespan for the first time

frontend/src/app/components/block-rewards-graph/block-rewards-graph.component.ts

@@ -64,7 +64,7 @@ export class BlockRewardsGraphComponent implements OnInit {
       .fragment
       .subscribe((fragment) => {
         if (['24h', '3d', '1w', '1m', '3m', '6m', '1y', '2y', '3y', 'all'].indexOf(fragment) > -1) {
-          this.radioGroupForm.controls.dateSpan.setValue(fragment, { emitEvent: true });
+          this.radioGroupForm.controls.dateSpan.setValue(fragment, { emitEvent: false });
         }
       });