Use statistics cards in storage usage quota

What does this MR do and why?

It re-introduce !79525 (merged) after being reverted, adjusting the behavior when storage limit isn't set and keeping the change behind a feature flag.

It uses the StatisticsCard component added in !80261 (merged) in usage_quota storage app (group's usage quota > storage).

Screenshots

	no purchase	with purchase
within limit
excess storage

How to set up and validate locally

Enable feature flag

In rails console run to use the new design:

Feature.enable(:update_storage_usage_design)

Add dummy storage data

1. create a new group
2. create a project inside the new group (choose a template or keep the README.md file to use storage)
3. from rails console run:

• n = Group.find_by(name: "GROUP_NAME_HERE")
• to add purchased storage run: n.additional_purchased_storage_size = 1 followed by n.save!
• to add storage limit run: n.additional_purchased_storage_size = 1 followed by n.save!

1. to add more storage to a project:

• p = Project.find_by(name: "PROJECT_NAME_HERE")
• p.statistics.update!(repository_size: 3145600)

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.

Related to #350646 (closed)