show quiz status as succeeded when fp=maxfp

What does this MR do?

• properly displays the status of the quiz as it is interpretated internally
• (previously, if the user had exactly as many mistakes as allowed it succeeded but was shown as failed)

How confident are you it won't break things if deployed?

quite

Links to related issues

Checklist

• added a test, or explain why one is not needed/possible...
• no unrelated changes
• asked someone for a code review
• joined #foodsharing-beta channel at https://slackin.yunity.org
• added an entry to CHANGELOG.md (description, merge request link, username(s))