[SM Cloud Licensing Trials] Improve Zuora Subscription Name Fields on Licenses Page in CDot Admin

Problem

In [SM Cloud Licensing Trials] Iteration 1.2: Upda... (&16047), we introduced provisioning/deprovisioning, activation, and usage of Self-managed cloud licensing trials.

On the Licenses page in CustomersDot admin, these cloud trial licenses get displayed alongside other license types.

Cloud licensing trials are not stored in Zuora and currently use a generated subscription name provided by CustomersDot. However, the attribute on the License model is named zuora_subscription_name, and the admin interface automatically tries to generate an external link to Zuora, which becomes a broken link for cloud licensing trials

The Subscription column also displays N/A for cloud licensing trials, which could be confusing when viewing the details of a license and seeing a subscription name already exists

Proposal

We could consider renaming this field's label to Subscription name on the admin page, and removing the link when the subscription name belongs to a trial

The Subscription column on the index page is a bit trickier. Right now, this actually contains the Zuora subscription ID with a link to a Zuora subscription, when available. We could consider just renaming this to Zuora subscription for additional clarity