Bug 1676759 - Prevent long email address from making the Firefox Account pane overflow horizontally. r=eoger

Differential Revision: https://phabricator.services.mozilla.com/D97601

browser/base/content/browser.xhtml

@@ -1348,10 +1348,13 @@
           <image role="presentation" id="fxa-menu-avatar"/>
           <vbox flex="1">
             <label id="fxa-menu-header-title"
-                   defaultLabel="&fxa.menu.signin.label;">&fxa.menu.signin.label;</label>
+                   crop="end"
+                   value="&fxa.menu.signin.label;"
+                   defaultLabel="&fxa.menu.signin.label;"/>
             <label id="fxa-menu-header-description"
                    crop="end"
-                   defaultLabel="&fxa.menu.turnOnSync.label;">&fxa.menu.turnOnSync.label;</label>
+                   value="&fxa.menu.turnOnSync.label;"
+                   defaultLabel="&fxa.menu.turnOnSync.label;"/>
           </vbox>
         </toolbarbutton>
         <toolbarseparator/>