UX: Minor improvements to invites (#12324)

* FIX: Show resend button only if an email was sent

Otherwise, show the "save and send email" button.

* UX: Copy change

* UX: Show feedback when link was copied

app/serializers/invite_serializer.rb

@@ -4,6 +4,7 @@ class InviteSerializer < ApplicationSerializer
   attributes :id,
              :link,
              :email,
+             :emailed,
              :redemption_count,
              :max_redemptions_allowed,
              :custom_message,
@@ -18,6 +19,14 @@ class InviteSerializer < ApplicationSerializer
     options[:show_emails] && !object.redeemed?
   end
 
+  def include_emailed?
+    email.present?
+  end
+
+  def emailed
+    object.emailed_status != Invite.emailed_status_types[:not_required]
+  end
+
   def expired
     object.expired?
   end