UX: Do not add leading/trailing spaces when copying API key in Firefox

If there is any other whitespace in the container, then Firefox will add a leading/trailing space when double clicking the key. This commit wraps the key in a div with no whitespace, to work around the problem.

app/assets/javascripts/admin/templates/api-keys-show.hbs

@@ -6,7 +6,7 @@
 <div class="api-key">
   {{#admin-form-row label="admin.api.key"}}
     {{#if model.revoked_at}}{{d-icon 'times-circle'}}{{/if}}
-    {{model.key}}
+    <div>{{model.key}}</div>
   {{/admin-form-row}}
 
   {{#admin-form-row label="admin.api.description"}}