feature/add-email-visibilty-toggle: Updated email visibility settings and conditions in UI

Added hint for email visibility to logged-in users and adjusted conditions for email display to users who have opted to show their email.

app/views/settings/index.html.erb

@@ -185,6 +185,9 @@
       <%= f.label :show_email, "Show Email Address:",
         :class => "required" %>
       <%= f.check_box :show_email %>
+      <span class="hint indent">
+        Only shown to logged-in users
+      </span>
     </div>
 
     <div class="boxline">

app/views/users/show.html.erb

@@ -100,7 +100,7 @@
     <div style="clear: both;"></div>
   <% end %>
 
-  <% if @user.is_admin? && @user.show_email? %>
+  <% if @user&.is_admin? || @user&.show_email? %>
     <label class="required">E-Mail:</label>
     <span class="d">
       <%= @showing_user.email %>