Bug 1847966 - Let the message-bar flex when where is not enough horizontal space. r=aleca

Differential Revision: https://phabricator.services.mozilla.com/D185896

--HG--
extra : amend_source : edf2273a0841ee8c6c97b4b3ed62114ee48311fd

mail/themes/shared/mail/message-bar.css

@@ -248,6 +248,7 @@ button.ghost-button:not(.semi-transparent):enabled:hover:active {
 /* Infobars styling. */
 .notification-content {
   flex-grow: 1;
+  flex-wrap: wrap;
   display: flex;
   margin: 0;
   margin-inline-start: 8px;