Add additional fields to assessment API schema [SA-21382]

[jleckie]

Summary

• Adds specificationAssessmentId, markVisibility, markType, and description to the assessment-item schema
• markVisibility is an integer enum (0=Staff Only, 1=Staff & Student, 2=Staff, Student & Parent) applicable to dueWork, quiz, project, LTI
• markType is a string slug enum applicable to dueWork, quiz, project
• Both specificationAssessmentId and description apply to all assessment types

Notes

• This PR should be merged after the corresponding schoolbox implementation PR for SA-21382
• Targets develop

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[Brahmah]

Who writes code by hand anymore?! 💀🚀📈