Missing Paste Image inside common editor

Summary

PASTE IMAGE (Ctrl + V) inside common editor is not working or uploading image to anywhere.

Steps to reproduce

Create a .md file, click in Edit

Try to paste image from Clipboard (nothing happens)

What is the current bug behavior?

Nothing happens

What is the expected correct behavior?

Image is upload to a storage or is staged with the current commit after paste (CTRL + V)

examples of working:

1. Web IDE
2. Issues
3. Comments

Output of checks

This bug happens on GitLab.com /label reproduced on GitLab.com

Results of GitLab environment info

Expand for output related to GitLab environment info

(For installations with omnibus-gitlab package run and paste the output of:
`sudo gitlab-rake gitlab:env:info`)

(For installations from source run and paste the output of:
`sudo -u git -H bundle exec rake gitlab:env:info RAILS_ENV=production`)