fix: lectures listing

[ruilopesm]

No description provided.

[reviewpad]

AI-Generated Summary: This pull request is primarily focused on fixing a bug in the listing of lectures within the BokkenWeb application. Changes have been made in the LectureView module of the BokkenWeb app. The alias for BokkenWeb.FileView has been replaced with BokkenWeb.FileJSON indicating a shift in the way files are being managed or presented. Additionally, when rendering the files associated with a lecture, the file.json template is no longer used for rendering each file. Instead, the data/1 function of the FileJSON module is employed to handle each file in the lecture.files list.