A build "weapon" is not a weapon (#6918)

* A build "weapon" is not a weapon

https://www.youtube.com/watch?v=a89ChTdUFrc

* whoops

core/src/mindustry/type/weapons/BuildWeapon.java

@@ -20,6 +20,8 @@ public class BuildWeapon extends Weapon{
 
     {
         rotate = true;
+        noAttack = true;
+        predictTarget = false;
         bullet = new BulletType();
     }
 
@@ -30,9 +32,7 @@ public class BuildWeapon extends Weapon{
 
     @Override
     public void update(Unit unit, WeaponMount mount){
-        //no
         mount.shoot = false;
-        //yes
         mount.rotate = true;
 
         //always aim at build plan