Fix bug with sending test email. JS error#204

oleksandr-mykhailenko merged 1 commit intomastermailgun/wordpress-plugin:masterfrom

DE-1491-wordpress-mailgun-2-1-4-updated-bug-config-test-not-workingmailgun/wordpress-plugin:DE-1491-wordpress-mailgun-2-1-4-updated-bug-config-test-not-workingCopy head branch name to clipboard