grades library Null safety

Classes

CourseGradesItem: Interface to display a CourseGrade.
DropDownGrades: DropDown to change the currently displayed grade list selecting a management. Triggers ManagementChanged.
GradeListBloc: Manages the logic related to grades, retrieving them when GradeListRequested is added and updating the GradeListState.selectedManagement.
GradeListEvent: Base class for GradeListBloc events.
GradeListRequested: Triggered when grades have been requested.
GradeListState: State of GradeListBloc.
GradesBar: Graphic bar for CourseGrade.semestralGrade, divided by each CourseGrade.partials and CourseGrade.finalExam, based on their weight.
GradesPage: Page to list grades. Initializes GradeListBloc and its repositories and providers.
GradesView: View for GradesPage.
ManagementChanged: Triggered when the selected management has changed to update the current selected grade list (that is shown to user).
SemestralGradeCard: Interface to display only CourseGrade.course.subject and CourseGrade.semestralGrade from a CourseGrade.
SingleGradeBar: Graphic bar to display a grade over 100, similar to a progress bar.

GradeListRequestStatus: Status for the http request made to retrieve grades.