All Submissions:

• Have you followed the Newspack Contributing guideline?
• Does your code follow the WordPress' coding standards and VIP Go coding standards?
• Have you checked to ensure there aren't other open Pull Requests for the same update/change?

Changes proposed in this Pull Request:

Closes https://app.asana.com/1/26890605006346/project/1205919985867982/task/1209464932054166?focus=true

This PR fixes an issue where updating a provider does not always refresh the subscriptions lists associated with that provider until a page reload. This happened because subscriptions lists would rerender when the provider was updated, but before api credentials were stored and settings were saved. As a result updating the provider would cause the subscriptions lists to fetch using the outdated provider details.

We fix this by:

• Only rerendering subscriptions lists when provider updates AND lists are not locked
• Correctly locking lists depending on provider update conditions

How to test the changes in this Pull Request:

Onboarding

1. Reset newspack via the reset newspack link at the bottom of any wizard
   
2. Navigate to Audience > Setup > Email Service Provider, and click the button to do the ESP step
3. Confirm the subscriptions lists section is not visible
4. Select an ESP provider and enter valid credentials
5. Confirm the subscriptions lists section appears and renders the expected lists

Switching Providers

1. Select a different provider
2. Confirm the subscriptions lists section renders a warning to save before editing subscriptions lists
3. Enter valid credentials for the new ESP
4. Confirm the subscriptions lists section renders the expected lists after loading

Bonus: Smoke test the ESP and Subscriptions Lists settings with invalid credentials, etc.

Other information:

• Have you added an explanation of what your changes do and why you'd like us to include them?
• Have you written new tests for your changes, as applicable?
• Have you successfully ran tests with your changes locally?