On mobile, show power of ten difficulty instead of full number

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

@@ -43,7 +43,8 @@
       <tr *ngFor="let diffChange of diffChanges.data">
         <td><a [routerLink]="['/block' | relativeUrl, diffChange.height]">{{ diffChange.height }}</a></td>
         <td>&lrm;{{ diffChange.timestamp * 1000 | date:'yyyy-MM-dd HH:mm' }}</td>
-        <td>{{ formatNumber(diffChange.difficulty, locale, '1.2-2') }}</td>
+        <td class="d-none d-md-block">{{ formatNumber(diffChange.difficulty, locale, '1.2-2') }}</td>
+        <td class="d-block d-md-none">{{ diffChange.difficultyShorten }}</td>
         <td [style]="diffChange.change >= 0 ? 'color: #42B747' : 'color: #B74242'">{{ formatNumber(diffChange.change, locale, '1.2-2') }}%</td>
       </tr>
     </tbody>