Add iCloud in CI for basic API test

https://github.com/steilerDev/icloud-photos-sync/blob/main/.github/actions/test/api/action.yml
We may only be able to perform simple login validation. Is this necessary?

Start by reviewing the referenced .github/actions/test/api/action.yml and the repository's existing API-test workflow. Determine how the proposed iCloud login validation would fit the CI setup and what credentials or service access it requires; done means the scope and necessity of the basic API test are resolved.

Written by the indexing model from the issue text.