Collabora buttons are not displayed in the attachments tab

[oanalavinia]

Steps to reproduce

1. Install collabora and enable it
2. Go to a page and select the attachments tab

Expected result:
For existing attachments you can see the edit with collabora action. Also, the button for creating a new office file is displayed at the button of the attachments list

Actual result:
None of the collabora buttons is displayed

[oanalavinia]

This is caused by some changes done as part of #7