GitLab.com trial form in 11.2.0-rc2-ee doesn't present group picker on submit

Summary

When attempting to start a GitLab.com trial from https://gitlab.com/profile/billings, we send the user to https://customers.gitlab.com/trials/new?gl_com=true. After submitting the form on this page, the user should be presented with a picker to select the namespace they'd like to apply the trial to.

Steps to reproduce

• Go to https://gitlab.com/profile/billings, click Start your free trial.
• Fill out the form presented and submit.

What is the current bug behavior?

User is presented with a "Successfully authenticated from GitLab account" banner and the form fields clear.

What is the expected correct behavior?

User should be presented with the namespace picker. They should be able to specify a namespace and apply a trial.

Other reports:

• https://gitlab.com/gitlab-com/marketing/general/issues/2706#note_92533983
• https://gitlab.com/gitlab-org/gitlab-ee/issues/6983#note_92652575

Output of checks

(If you are reporting a bug on GitLab.com, write: This bug happens on GitLab.com)

Results of GitLab environment info

Expand for output related to GitLab environment info

(For installations with omnibus-gitlab package run and paste the output of:
sudo gitlab-rake gitlab:env:info)
(For installations from source run and paste the output of:
sudo -u git -H bundle exec rake gitlab:env:info RAILS_ENV=production)

Results of GitLab application Check

Expand for output related to the GitLab application check

(For installations with omnibus-gitlab package run and paste the output of:
sudo gitlab-rake gitlab:check SANITIZE=true)
(For installations from source run and paste the output of:
sudo -u git -H bundle exec rake gitlab:check RAILS_ENV=production SANITIZE=true)
(we will only investigate if the tests are passing)

Possible fixes

(If you can, link to the line of code that might be responsible for the problem)