New subscription purchase flow for Trial namespaces should follow new path
Summary
When a namespace is on a trial and it is active, a user trying to purchase a new subscription for that namespace is pointing to a the legacy new subscription flow. Not only does this cause an inconsistent user experience, but it causes the user to receive an error during checkout due to not having a stored address.
Proposal
Update the path for this use case to point to the new subscription purchase flow (via GitLab.com) so that address is collected during the purchase process.
Reference
Additional details of this change request is described here: #1236 (comment 442674321)