Add Privacy Pro surveys to macOS

[samsymons]

Task: https://app.asana.com/0/1207619243206445/1208041703530761/f

This PR adds the Privacy Pro surveys to the macOS app.

How to test the subscriber survey:

1. Update the client to use the staging URL below
2. Sign into a Privacy Pro account, and, if necessary, hardcode the privacyProDaysSinceSubscribed initializer value in RemoteMessagingConfigMatcherProvider to be 14 or above
3. Update the shouldProcessConfig func in BSK to always return true, for testing multiple cases
4. Test that when you relaunch the app, the subscriber survey appears
5. Now hardcode the privacyProDaysSinceSubscribed value to be below 14
6. Relaunch the app and verify that the survey is gone

How to test the exit survey:

1. Now we need to test an expiring account; update RemoteMessagingConfigMatcherProvider line ~94 to set isPrivacyProSubscriptionExpiring to true and all other booleans to false
2. Relaunch the app and verify that the exit survey shows up

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[github-actions]

Your PR is hosted at https://staticcdn.duckduckgo.com/remotemessaging/config/staging/macos-config.json

[jaceklyp]

Works for me! gj :)