Lengthen Veigars E's CDT

I get that the stun needs to be somewhat long for his W to combo nicely and needs to be up for helping stack his AP passive. But being able to deploy it 3-4 times over a single fight is pretty broken given its decent cast range, large AOE, and long stun duration. Also, since 1k AP is not hard to achieve on Veigar, anytime you get hit, means at least a solid chunk of your health (like a quarter, but usually closer to 75% or a near one shot depending on your defense) is gone.