Summary:
- Adding confirmation dialog when user doesn't want to cancel site
- Changing `Cancel subscription` to `Cancel plan`
- Removing `Pro` from upgrade header on pricing modal
- Better handling situation when there is no default price
- Removing mentions about sprouts program
- Removing cache for stripe plans
Test Plan: Updated tests
Reviewers: georgegevoian
Reviewed By: georgegevoian
Differential Revision: https://phab.getgrist.com/D4273
7f28aee79c