Applying more liberal editor config policy (#17125)

Prior to this commit, only those who could create posts could edit their confi

However, we are allowing users who can't create posts to edit posts.  So
we want to allow for them to change their editor configuration.

Revisits
- forem/forem#16516

Supplants
- forem/forem#16778

Related to
- forem/forem#17123
- forem/forem#16908

app/views/users/_customization.html.erb

@@ -40,7 +40,7 @@
     </div>
   </div>
 
-  <% if policy(Article).create? %>
+  <% if policy(Article).has_existing_articles_or_can_create_new_ones? %>
   <div class="crayons-card crayons-card--content-rows">
     <h2 class="crayons-subtitle-1">
       <%= t("views.settings.custom.writing") %>