Remove limit of four features per plan

What does this MR do?

The billings page displays each available plan and a feature list for each plan. At the moment, there is a limit of four features displayed per plan -- this was intended so as not to have a very long list.

As the lists are not that long right now, we should remove this limit and show the customers the full feature list.

Related issue: https://gitlab.com/gitlab-org/gitlab/-/issues/287677

Screenshots

Before	After

How to test locally

• Run locally the https://gitlab.com/gitlab-org/customers-gitlab-com project
• In your local GitLab app, go to a group's billing page. The URL is of the form http://[gitlab-url]/groups/[namespace]/-/billings. You should see the updated, long feature lists.

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• Code review guidelines
• Merge request performance guidelines
• Style guides