Adapt subscriptions page for free plans and trials
The subscription table from #https://gitlab.com/gitlab-org/gitlab-ee/issues/7772 contains some information that doesn't apply to free plans and trials, so in those cases, some cells are left empty.
This can cause confusion, so it would be better to remove those cells from the table altogether.
Free subscription
Free subscriptions don't have an end date, a billing cycle, or can go over their usage, so they only need to show two pieces of information that ca be displayed in the Usage
row.:
- Seats currently in use. This is the number of seats they will be required to purchase if they upgrade to a paid plan. This will be explained in a popover
- Subscription start date. This may be useful to users in certain cases. For example, if they were previousy on a paid plan, this would let them know when it ended.
Trial
Trials need the same information as free subscriptions, in addition to the trial's end date.