File manager breaks when attempting to reference moment

[kaidesu]

Describe the issue

Due to replacing the way momentjs is referenced, a reference to the old method was left behind within the file manager.

Should be this.$moment() instead of $moment()

To reproduce

1. Upload any file to the file manager

Version and browser

Version: v6.0.0 beta 0

Bug report checklist

• I have filled out as much information as I can
• I have detailed how the issue can be reproduced
• I have searched for existing issues and to the best of my knowledge this is not a duplicate