Update Beachball.tsx to remove duplication in strict mode (#840)

in strict mode the beachball gets rendered twice

packages/react-identicon/src/icons/Beachball.tsx

@@ -10,9 +10,12 @@ import { beachballIcon } from '@polkadot/ui-shared';
 function Identicon ({ address, className = '', size, style = {} }: Props): React.ReactElement<Props> {
   const updateElem = useCallback(
     (node: HTMLDivElement): void => {
-      node?.appendChild(
+      if (node) {
+        node.innerHTML = '';
+        node.appendChild(
           beachballIcon(address, { isAlternative: false, size })
         );
+      }
     },
     [address, size]
   );