Bug 1682023 - Let the composer title bar title crop at the end to not let to grow the window. r=mkmelin

mail/components/compose/content/messengercompose.xhtml

@@ -836,7 +836,7 @@
         </hbox>
       </hbox>
       <hbox id="titlebar-title" align="center" flex="1">
-        <label id="titlebar-title-label" value="&msgComposeWindow.title;" flex="1"/>
+        <label id="titlebar-title-label" value="&msgComposeWindow.title;" flex="1" crop="end"/>
       </hbox>
       <hbox id="titlebar-fullscreen-button"/>
     </hbox>