Bug 1572807 - Truncate very long origins properly in about:logins header. r=MattN

Differential Revision: https://phabricator.services.mozilla.com/D41420

--HG--
extra : moz-landing-system : lando

browser/components/aboutlogins/content/components/login-item.css

@@ -50,6 +50,8 @@
   margin-top: 0;
   margin-bottom: 0;
   flex-grow: 1;
+  overflow: hidden;
+  text-overflow: ellipsis;
 }
 
 .delete-button,
@@ -246,7 +248,7 @@ a.breach-alert-link {
       --reveal-checkbox-opacity-active: .6;
       --success-color: #86DE74;
     }
-  
+
     .breach-alert {
       box-shadow: 0 2px 8px 0 rgba(249,249,250,0.1);
       color: #0C0C0D;