[T-3330] [RELEASE] Student registered in two classe

A problem was detected involving the creation of two classes on the same dates for a student. To address this issue and prevent future inconveniences, the following enhancements have been made to the system:

• Validation in the Course Section: A validation has been added to the course section to prevent the creation of courses with dates that do not fall within the established enrollment period (arrival start date and departure start date of enrollment). This solution involves directly blocking dates that are not allowed on the calendar.

• Validation in the Class Section: An additional validation has been introduced in the class section to avoid date overlap. This means that a class cannot be added on a date where another class is already scheduled. Additionally, date blocking has been implemented on the calendar to ensure that classes fit within the established course range.

With these improvements, the system now ensures that classes or courses cannot be added that overlap in time. Furthermore, it prevents the introduction of dates where the end date is before the start date, or vice versa. 

Starting today, February 28th, 2024, any classes or courses created should not appear duplicated.