Add config action for Config::clear()

This action is tricky because it undoes what other actions might do. I'm not sure. Also the examples given here are all changing config entity stuff - manipulating block visibility with actions might deserve it's own action.

I created ✨ Create a setVisibility config action to change a block's visibility Active as the proper approach to solve the issue presented here.

Closing this issue as the clear approach undoes what other actions might do, and goes against recipes goal of being non-destructive.