Support Multi-Studyset Practice Tests via Term Mappings

[google-labs-jules]

This change transitions practice tests from a single studyset_id relationship to a many-to-many relationship derived from the terms included in the test.

Key changes:

• Modified PracticeTest model and GraphQL resolvers to remove direct studyset_id usage.
• Implemented a new studysetIds field on PracticeTest that queries unique studyset IDs from both question and distractor terms.
• Updated RecordPracticeTest and UpdatePracticeTest mutations to automatically calculate questionsCorrect and questionsTotal from the provided questions array.
• Refactored dataloaders to join practice_tests with practice_test_question_terms and practice_test_distractor_terms.
• Updated integration tests to provide full term objects (ID, term, def) required by the new TermATP type and to reflect the removed studysetId input.

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PR created automatically by Jules for task 10523823744295046263 started by @ehanahamed

[google-labs-jules]

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