So I had mine without the bearing, just resting the cone inside the topmount. Not the best solution, but it sort of worked.
You NEED a bearing at the top !
When you steer, the whole strut turns with the wheel; so the top bearing allows the whole strut/spring to turn freely against the fixed topmount.
With no bearing, all sorts of nastiness will happen - the spring will twist & stress when you steer, steering will become heavy and will tend to spring back to centre, you'll get clunks and twangs when you steer; or the spring
might turn but either the top of it will grind away at your top mount and cause damage, or the bottom end will turn against the bottom spring platform and cause damage there.