For something like this that, could, possibly, maybe, etc., be a safety issue "in the future" (tomorrow, next week next month, etc.), I think you'd be smart to have it corrected as the buyer requests.
If you DO decide to have it corrected, be sure to allow the buyer to choose the licensed electrician. That way, if there's ever a problem and they buyer even thinks about filing a lawsuit, you can say..."I didn't choose the electrician...YOU DID."
And one more thing...if you do decide to fix it, have the buyer increase their deposit in escrow by the amount of the repair. That way, the buyer has more "skin in the game" and if the buyer later decides to back out of the contract, YOU are not out any money for the repairs the buyer requested.
Ed