API-based checks should run nightly and be mocked for CI

[MantisClone]

The payment-detection tests rely on explorer APIs. These API-based checks should run nightly.

New tests should be written that use mocks.

This should eliminate the need for external fork detection, added in #1030.

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Migrated from Asana: https://app.asana.com/0/1203912381456855/1205300974037118/f

[MantisClone]

We want to increase external contributors. We need this to allow external contributors without sharing secrets.