unify native modals

app/views/shared/_turbo_modal.html.erb

@@ -1,5 +1,4 @@
 <% if turbo_native_app? %>
-  <% content_for(:native_modal, 'true') %>
   <% content_for(:native_title, local_assigns[:title]) if local_assigns[:title] %>
   <turbo-frame id="modal">
     <native-modal class="block max-w-lg mx-auto <%= turbo_native_android? ? 'pb-4' : 'pb-6' %>" data-close-after-submit="<%= local_assigns.key?(:close_after_submit) ? local_assigns[:close_after_submit] : true %>">