Display course module read open time in course page boxes

Currently module read open time is not displayed in the boxes on the course home page. 

<img width="640" height="391" alt="Image" src="https://github.com/user-attachments/assets/b8e14c73-90ab-4bed-b70f-bf1d48cf4887" />

The open time for reading could be added next to the currently displayed opening time for exercise submissions.