fix: Execute the messenger:consume command as www-data

[marien-probesys]

Related issue(s)

N/A

How to test manually

1. Remove the app/var/cache and app/var/log folders
2. Start the stack and wait until that the worker is healthy
3. Verify that the folders have been recreated and are owned by your own user (or www-data in prod)

Reviewer checklist

• Code is manually tested
• Interface works on both mobiles and big screens
• Interface works on both Firefox and Chrome
• Tests are up to date
• Documentation is up to date
• Pull request has been reviewed and approved