Remove left over console debugging code in file upload module

I can see this comes from Andrew's general comment in MDL-70947 https://tracker.moodle.org/browse/MDL-70947?focusedCommentId=845609&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-845609 - however it seems clear that this is merely an example, as it makes no sense to implement this in production code but was mistakenly taken as instruction

This was actually questioned during integration https://tracker.moodle.org/browse/MDL-70947?focusedCommentId=853187&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-853187

Unless there is a genuine purpose for logging random DOM elements to the console, it should be removed - ping huongn@moodle.com, maybe you remember more?