Allow using Assassinate's 5th hit midair

For as relatively small the gains are dashing over standing nates (2.5/11% dummy without/with SE assuming a wide enemy you don't need to about face after dashing to continue hitting), reliably getting the dashes off can be surprisingly difficult. If you take damage and are knocked slightly off the ground for a few frames at the same time you try to dash your nate, you will instead just walk, costing dpm. This may sound like an unlikely or infrequent alignment but it's quite the opposite, and I often even get several consecutive interrupted dashes. If there is insufficient smoke or a high enough acc boss, this will in many cases lead to a net loss in dpm vs the less active gameplay of standing spam. I propose that the foothold requirement for the dash be removed so that the more active gameplay has better odds of netting greater dpm.

There are also implications for situations like attacking from right head platform, getting a left kb from magic as your nate ends, and dashing back onto rh plat from midair, which I feel is a worthwhile and rewarding upgrade for concentrated players.