Added FOCUS-45024 - Delete a Student: Resolve Errors Deleting a Student

This update addresses two issues related to deleting students. First, it resolves a foreign key violation error that occurs when deleting a student with records in the 'teacher_student_flags' table by adjusting the query logic in 'DeleteStudent'. Second, it improves address merging to prevent unique key violations by implementing query modifications that handle these conflicts proactively during the deletion process.

Added FOCUS-45556 - Cannot delete student