optimize addresses page

the longest part of addreses page loading was fetching validation
count for every address.

addresses are loaded from cache. it takes less than a second but
fetching validation count takes more than 5 seconds.

Moreover, validation_count is not used.

apps/block_scout_web/lib/block_scout_web/controllers/address_controller.ex

@@ -44,8 +44,7 @@ defmodule BlockScoutWeb.AddressController do
           index: index,
           exchange_rate: exchange_rate,
           total_supply: total_supply,
-          tx_count: tx_count,
+          tx_count: tx_count
-          validation_count: validation_count(address.hash)
         )
       end)
 

apps/block_scout_web/lib/block_scout_web/templates/address/_tile.html.eex

@@ -29,11 +29,6 @@
       <span data-test="transaction_count">
         <%= @tx_count %>
       </span> <%= gettext "Transactions sent" %>
-      <% if validator?(@address) do %>
-        <span data-test="validation_count">
-          <%= @validation_count %>
-        </span> <%= gettext "Validations" %>
-      <% end %>
     </span>
   </td>
 </tr>