/sites/site_id/files endpoint does not respect pagination

[styxlab]

According to the documentation, requests that return multiple items are paginated and should return pagination info on the response header. However, when querying endpoint

/sites/site_id/files?page=1&per_page=10

I always get all items returned and the link header is absent. In contrast

/sites?page=1&per_page=10

works as expected and a link header is returned. As the files endpoint may return huge lists, pagination is really needed. I hope this can be fixed.