*Related PR link*: https://github.com/edx/edx-platform/pull/19441
*Related Jira Ticket link*: https://openedx.atlassian.net/browse/OSPR-2904
*Note*: This PR is made to fix the issues caused in the [related PR](https://github.com/edx/edx-platform/pull/19441)
Currently textbooks for a course are not loaded in i-frame. Reason is that browser cannot find the resources required to load the viewer. In file /lms/templates/pdf_viewer.html, all static urls e.g.
have unnecessary /static in the beginning of paths, due to which, the viewer is not loaded correctly and textbooks are not displayed correctly.
So I have removed those unnecessary `/static`(s) from the source paths.