Ensure that whitespace doesn't case adding members to fail

CHANGELOG

@@ -2,6 +2,7 @@ Please view this file on the master branch, on stable branches it's out of date.
 
 v 8.13.0 (unreleased)
   - Truncate long labels with ellipsis in labels page
+  - Adding members no longer silently fails when there is extra whitespace
   - Update runner version only when updating contacted_at
   - Add link from system note to compare with previous version
   - Improve issue load time performance by avoiding ORDER BY in find_by call

app/assets/javascripts/users_select.js

@@ -261,10 +261,11 @@
                   }
                 }
                 if (showEmailUser && data.results.length === 0 && query.term.match(/^[^@]+@[^@]+$/)) {
+                  var trimmed = query.term.trim();
                   emailUser = {
                     name: "Invite \"" + query.term + "\"",
-                    username: query.term,
-                    id: query.term
+                    username: trimmed,
+                    id: trimmed
                   };
                   data.results.unshift(emailUser);
                 }