Adding to wait for ajax to finish on page for DeveloperHub

I cannot reproduce the CI fails locally, but I added this extra waits that will help. We have ajax refresh on all the pages.

http://qa-selenium.mv.mozilla.com:8080/view/Marketplace/job/marketplace.stage.developer_hub.saucelabs/lastCompletedBuild/testReport/tests.desktop.developer_hub.test_developer_hub/TestDeveloperHub/test_hosted_paid_app_submission/
http://qa-selenium.mv.mozilla.com:8080/view/Marketplace/job/marketplace.dev.developer_hub/85/console