attachments are not returned by solr when the locale does not match the default locale

Example of STEPS TO REPRODUCE

1. Set the wiki to be Multilingual (EN and FR)
2. Translate a page in FR
3. Upload some image file attachments to this page from Attachments tab
4. Switch to FR translation
5. Edit the page with CKEditor
6. Click on 'Image' from the toolbar

EXPECTED RESULTS

The image attachments uploaded previously on the page are displayed in Gallery.

ACTUAL RESULTS

The images are not displayed. However, if switched to EN version, the images are shown.

Alternative scenario:

In a multilingual wiki, switch the local of the UI to a non-default one (e.g., FR).
Use the top-right search bar to search for a know attachment.
The attachment is not returned