I'm trying to migrate from Jira Server to Jira Cloud per this guide. However, when I'm logged into Jira Cloud, I do not see an option for "Jira Import." My only options are: "Backup manager", "External System Import", and "Restore system." The "Restore system" option allows me to specify a .zip file from which to restore, but not attachments, avatars, and logos. What should I do?