Issue:
When a student chooses to preview a course by selecting "Preview" before entering, The SCORM API sets "cmi.mode" flag to "normal" so the content assumes that this is a new (normal) attempt and starts sending tracking data.
Upon exiting the sco, Moodle assumes that it was attempted, and marks the sco as "incomplete", even though the user only wanted to preview the course.

The expected behavior is to set the "cmi.mode" to "browse" according to SCORM 2004 specs. and this was done correctly in version 2.3+, so this issue is probably a regression from 2.3.

Steps to reproduce the issue:
1. Upload a SCORM 2004 compliant package.
2. Enter package in "Preview" mode, the word "Preview" is displayed above the TOC.
3. Moodle sets the "cmi.mode" to "normal" instead of "browse".
4. Moodle incorrectly marks the sco as "attempted".