Store creation M2: store summary -> WPCOM plan

[jaclync]

Project thread: pe5sF9-I3-p2
Design: HyVloP5FipZzyPVenH2euI-fi-2116%3A106887

After a site is created in the store summary screen, the user can tap the primary CTA to see the eCommerce plan and a CTA to purchase with IAP.

Testing guide: PdfdoF-1Ej-p2
Sandbox/proxy setup (Charles proxy is required): pb3aDo-OE-p2

Subtasks

• WPCOM plan screen with product from IAP Store creation M2: WPCOM plan screen (UI only) #8120
  - [ ] Integrate with IAP purchase and show the success/failure alerts update: we're going with web checkout for M2
• New checkout flow:
  • Networking layer changes Store creation M2: checkout flow - Networking layer changes #8203
  • Yosemite layer changes Store creation M2: checkout flow - Yosemite layer changes #8205
  • Checkout flow Store creation M2: checkout flow #8216
• Show loading UI while fetching IAP status p1668653541795519/1668565030.897709-slack-C045CUK1Y3U
  - [ ] Polish IAP error UI (right now it's an alert) update: there's no error with the updated checkout implementation
• Release: update expected product identifier
• Design polishes: Store creation M2: UI/UX updates #8271
  • Update icons (export ones that aren't in the app)
  • Accommodate long price text
  • Update refund info to be footnote style