Change download button position so it's not hidden on mobile

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

@@ -2,7 +2,7 @@
 
   <div class="card-header  mb-0 mb-md-4">
     <span i18n="mining.pools-dominance">Mining pools dominance</span>
-    <button class="btn" style="position: absolute; right: 30px" (click)="onSaveChart()">
+    <button class="btn" style="margin: 0 0 4px 0px" (click)="onSaveChart()">
       <fa-icon [icon]="['fas', 'download']" [fixedWidth]="true"></fa-icon>
     </button>