Remove hack's phantom melee

[Zephanos]

Summary

Balance "Removes phantom melee attack that can disrupt aim from explosive/taser hacks."

Purpose of change

Hacks, despite having no damage on their melee and probably not even intended to have melee, will still attempt hit their target. This attack while mostly inconsequential can disrupt survivor aim while issuing no prompt beyond sudden aim reduction.

Describe the solution

Adds "PACIFIST" as a default flag to base_drone that all hacks refer to and have actual melee hacks delete it from their flag list.

Describe alternatives you've considered

Adding a prompt or warning that the hack is disrupting your aim, though that seems like it would be better handled by dodge/speed vs aiming mechanics.
Doing the opposite and adding PACIFIST to every explosive hack instead but considering the drones that actually use melee are the outliers it seemed better to make it the default.

Testing

Tested all explosive/taser hacks and was able to maintain full aim until they detonated.
Tested Manhack and Bloodhound Drone from aftershock to make sure they could still melee, both attacked and killed the debug survivor.

Additional context

Hack melee

hack.melee.mp4

Hack pacified

hack.paci.mp4