Update locators on usage quota page

What does this MR do and why?

• Adding data-qa-selector to elements on usage quota page 👇
• First attempt to fix #347227 (closed)

Plan/Additional CI minutes	Purchased Storage

How to set up and validate locally

Run

bundle exec bin/qa Test::Instance::All https://staging.gitlab.com -- qa/specs/features/ee/browser_ui/fulfillment/purchase/purchase_ci_spec.rb

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.