Explorer: Show empty state when block has no transactions (#13259)

explorer/src/components/account/BlockHistoryCard.tsx

@@ -68,6 +68,9 @@ export function BlockHistoryCard({ slot }: { slot: number }) {
         </TableCardBody>
       </div>
 
+      {confirmedBlock.data.transactions.length === 0 ? (
+        <ErrorCard text="This block has no transactions" />
+      ) : (
         <div className="card">
           <div className="card-header align-items-center">
             <h3 className="card-header-title">Block Transactions</h3>
@@ -119,6 +122,7 @@ export function BlockHistoryCard({ slot }: { slot: number }) {
             </table>
           </div>
         </div>
+      )}
     </>
   );
 }