Update french footer text

[eleanorreem]

Overview

Update description of Bloom in the french site version in the footer. We store some of our translations in /messages folder.

Action Items

• [ ] Go to the french version of the site by navigating with the language menu at the top. Look at the footer to see the piece of text where Bloom is described.
• [ ] Look at the /bloom-frontend/messages/shared/fr.json to find the relevant string. Update the text according to the image below:
• [ ] Rebuild to site to ensure that it has been updated
• [ ] Run tests and linting to ensure nothing has been broken