fix(classroom): resolve type errors

[google-labs-jules[bot]]

This PR refactors the advanced service checks in the classroom directory to be more concise and robust, using a simplified check for the top-level Classroom object and its Courses property. This change ensures that the type checker can correctly infer the existence of the necessary properties while improving code readability.

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PR created automatically by Jules for task 17360807705286247641 started by @jpoehnelt

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