Fix topnav dropdown link hover state

apps/block_scout_web/lib/block_scout_web/templates/layout/_topnav.html.eex

@@ -9,7 +9,7 @@
     <div class="collapse navbar-collapse" id="navbarSupportedContent">
       <ul class="navbar-nav mr-auto">
         <li class="nav-item dropdown">
-          <a class="nav-link dropdown-toggle" href="#" id="navbarBlocksDropdown" role="button" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
+          <a class="nav-link topnav-nav-link dropdown-toggle" href="#" id="navbarBlocksDropdown" role="button" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
             <span class="nav-link-icon">
               <%= render BlockScoutWeb.IconsView, "_block_icon.html" %>
             </span>
@@ -28,7 +28,7 @@
           </div>
         </li>
         <li class="nav-item dropdown">
-          <a href="#" role="button" id="navbarTransactionsDropdown" class="nav-link dropdown-toggle" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
+          <a href="#" role="button" id="navbarTransactionsDropdown" class="nav-link topnav-nav-link dropdown-toggle" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
             <span class="nav-link-icon">
               <%= render BlockScoutWeb.IconsView, "_transaction_icon.html" %>
             </span>