fix: fixes typo in on track domains page

app/views/track_domains/index.html.haml

@@ -12,7 +12,7 @@
       %h2.noData__title There are no tracking domains for this server.
       %p.noData__text
         To use Postal's open & click tracking, you need to configure a domain that links will be re-written to use. Enable
-        message tracking by adding a sutiable tracking domain for your outbound e-mails.
+        message tracking by adding a suitable tracking domain for your outbound e-mails.
       %p.noData__button= link_to "Add a custom tracking domain", [:new, organization, @server, :track_domain], :class => "button button--positive"
 
   - else