Use Namespace Limits UI on pre-enforcement phase

What does this MR do and why?

This implements https://gitlab.com/gitlab-org/gitlab/-/issues/429652

This MR is dependent on !133516 (merged)

MR	Description
!133516 (merged)	Improvements to NamespaceStorageApp app data
!136463 (merged)	(👈 you're here) Use Namespace Limits UI on pre-enforcement phase

Screenshots or screen recordings

Before	After	Paid Group

How to set up and validate locally

For a better understanding of this feature please read through this MR's description: !133516 (merged)

To setup this scenario we need to change:

1. Feature.enable(:namespace_storage_limit_show_preenforcement_banner)
2. Gitlab::CurrentSettings.update!(repository_size_limit: 0)
3. Plan.free.actual_limits.update!(notification_limit: 1)

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.