Show which enforcement type is applied to a given namespace

What does this MR do and why?

This is the MR related to this issue https://gitlab.com/gitlab-org/gitlab/-/issues/413759

Summary of the changes

• Addresses this follow up comment: !125228 (comment 1458394448)
• Removes some remaining code around showProgressBar prop (also a follow up from !125228 (merged))
• Adds the subtitle proposed in https://gitlab.com/gitlab-org/gitlab/-/issues/413759 which indicates what enforcement type the namespace is currently. The learn more link should also be dynamic:
  • Project Storage Limit
  • Namespace Storage Limit
• Improves test coverage for the storage_usage_statistics_spec.js
• Removes unnecessary test in storage_statistics_card_spec.js since we show now always display the progress bar

Screenshots or screen recordings

Before	Project enforcement	Namespace enforcement

How to set up and validate locally

Numbered steps to set up and validate the change are strongly suggested.

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.