Full stop.

This is not a full sentence, but rather an expression (without a subject, predicate etc).

Shouldn't it have a full stop then?

No, maybe it should be deleted - or incorporated into a full sentence (this would be preferred here in Tatoeba, as always).

We usually don't leave expressions which are not full sentences. Many such contributions have recently been deleted. We encourage contributors to turn such expressions into full sentences.

I suggest someone to delete both sentences.

If you add a full stop, "Take a leap of faith" can still be seen as an imperative sentence (telling someone they have to take a leap of faith), so I guess the English one can stay.

Yes you are right. If the owner of the english sentence put a full stop, Turkish will be "Gözünü karart." as an imperative.

I can add a full stop to the English sentence, and then we can add a full stop to the Turkish as well. Do you think it's a good idea?

Done.
I added a full stop to the English, and I'll add a full stop to the Turkish sentence as well.

(and, of course, turned it into an imperative, omitting the -mak ending).