UI showing countdown for Free Trial of the Free plan, when Ultimate trial is ended early
# Bug
## Summary
When a customer requests ending an Ultimate trial early it has been common practice to place the group on the Free plan.
Now, when placing a group on the free plan, the UI displays a "Free trial...Day x/30"
This was first noticed in a customer ticket but have been able to replicate.
Related ticket: https://gitlab.zendesk.com/agent/tickets/507740
## Steps to reproduce
Sign up for an ultimate trial on a group `OhHappyDay`.
Used Mechanizer to end the trial early (changed the group plan to free)
(Mechanizer Pipeline https://gitlab.com/gitlab-com/support/toolbox/mechanizer/-/pipelines/1199252340)
Results in the UI displaying `Free trial` however the billing page reports correctly the change to Free:
{width="720" height="120"}
Using another group `ohhappydays` with another Ultimate trial, I used Admin tools to change the plan to 'Free'.
This had the same result with the 'Free trial' in the UI:
{width="747" height="138"}
Customers portal shows `trial = false` correctly for both groupst:
```
[+]Namespace information
id 66318000
name OhHappyDay
path ohhappyday
members_count_with_descendants 2
extra_shared_runners_minutes_limit
shared_runners_minutes_limit 400
billable_members_count 2
plan free
trial_ends_on 2024-04-03
trial false
```
Used Mechanizer to attempt to change `trial_ends_on` to end the trial early, but this had no effect, presumably because trial=false! (Pipeline: https://gitlab.com/gitlab-com/support/toolbox/mechanizer/-/pipelines/1199273204)
## What is the current _bug_ behavior?
From a trial subscription, we are unable to immediately place the namespace to free.
This seems to cause some potentially confusing messaging like the following on the billing page:

## What is the expected _correct_ behavior?
Dropping a group to free should result in the group being on the free plan immediately. There is no such thing as a trial of the Free plan.
## Workarounds
Does not appear to be a way around this - seems to be a UI issue only?
## Reported examples
1. https://gitlab.zendesk.com/agent/tickets/507740
2. https://gitlab.zendesk.com/agent/tickets/514700
issue