Fix concurrent asynchronous calls. (#675)

* Fix concurrent asynchronous calls.

* Remove test without mempool info websocket.

* Remove isloading$ variable.

frontend/src/app/components/blockchain/blockchain.component.html

@@ -1,8 +1,8 @@
 <div class="text-center" class="blockchain-wrapper">
   <div class="position-container">
     <span>
-      <app-mempool-blocks [isLoading$]="isLoading$"></app-mempool-blocks>
-      <app-blockchain-blocks [isLoading$]="isLoading$"></app-blockchain-blocks>
+      <app-mempool-blocks></app-mempool-blocks>
+      <app-blockchain-blocks></app-blockchain-blocks>
       <div id="divider"></div>
     </span>
   </div>