I sincerely do not believe this will affect the game's performance in the slightest. Fans have been waiting for GTA VI for so many years, so all this does is fuel imagination, hype and have players speculate - causing interest to go to the moon.
It's hardly the first time a prototype build of a game has leaked online. I remember there was an in-development build of Crysis 3 that leaked circa 2011 - didn't stop it from this game being one of my all-time favorites down the road.
I'm going to take the opportunity to call out on the "gaming media" and all game "journos" for their utter hypocrisy in their "condemnation" of the leaker's acts. They're like hounds around this. Legit spare me the drivel,
Kotaku leaked and published the Fallout 4 script verbatim years before release. Due to changes in the site that article no longer seems to have the documents posted directly, but
here is a copy. Anyone who played Fallout 4 at release or even now, roughly 7 years later, knows that is 100% accurate.