French translation missing for the child pages of Sandbox

Steps to reproduce:

1. Go to Administer Wiki
2. Click on Localization
3. Set the multilingual to No
4. Change the Supported Languages to French
5. Change the Default Language to French
6. Click on Save
7. Click on "Bac à sable" (Sandbox) from the left Navigation panel
8. Observe the title of the child pages
9. Click on the first child e.g. Sandbox Test Page 1
10. Observe the page title

Expected results: All text content is translated to french.

Actual results: The 3 child pages of "Bac à sable" are still in English: Sandbox Test Page 1, Sandbox Test Page 2, Sandbox Test Page 3