#7882172 Pass the plan interval to getWooExpressMediumFeatureSets

Fixes #74777

Proposed Changes

This lets us have slightly different copy for the annual vs the monthly plan. In particular, we want to make sure that monthly users don’t think they get chat support

Testing Instructions

• On an eCommerce trial site, visit the /plans/:siteSlug page.

  • You can create a new trial site by visiting /setup/wooexpress/.

• Select “Pay Monthly” and check under “General features”.

• “Get support 24/7” should read Need help? Reach out anytime via email.
  

• Select “Pay Anually” and check under “General features”.

• “Get support 24/7” should read Need help? Reach out anytime via email or chat.
  

Pre-merge Checklist

• Has the general commit checklist been followed? (PCYsg-hS-p2)
• Have you written new tests for your changes?
• Have you tested the feature in Simple (P9HQHe-k8-p2), Atomic (P9HQHe-jW-p2), and self-hosted Jetpack sites (PCYsg-g6b-p2)?
• Have you checked for TypeScript, React or other console errors?
• Have you used memoizing on expensive computations? More info in Memoizing with create-selector and Using memoizing selectors and Our Approach to Data
• Have we added the “[Status] String Freeze” label as soon as any new strings were ready for translation (p4TIVU-5Jq-p2)?
• For changes affecting Jetpack: Have we added the “[Status] Needs Privacy Updates” label if this pull request changes what data or activity we track or use (p4TIVU-ajp-p2)?