Griffon QoL suggestion: More endurance

I think it would be nice if the griffon had 2 endurance stacks instead of only 1. Right now we can't "store" Wing Flap charges like we can with the Raptor's jump or with the Jackal's dash, we only have one that refils at a regular rate.

Of course just adding one charge would be a buff, because then we would gain an additional boost to gain altitude when starting from the ground (by flapping twice instead of once), so in order to keep things balanced, it should only refill to 1 charge when we're not flying, and the second charge would only refill while airborne.

The idea is not game-changing, it is simply that if we just glide with our griffon for a while without using Wing Flap, we would have 2 stored charges instead of one, making maneuvring easyer in case we suddenly need to regain altitude. It would also make us more free when trying to maintain altitude, because we could wait a little while before having to Wing Flap again without loosing any efficiency, instead of having to spam it as soon as the endurance bar is full.