Modify unregisterField method

[Mammadbayli]

When dynamically creating controls and registering them, they are not deallocated when they are unregistered, I figured the cause could probably be the fields dictionary keeping a reference to them.
Here is my snippet of code:

 merchant.visibleParams?.map { $0.associatedControl }.forEach { control in
            control.onChange = { _ in self.validate() }
            self.validator.registerField(control, rules: [RequiredRule()]) //here I register
            section.elements.append(control)
   }

When I update the UI and unregister those controls, they are not deallocated:

   node.subnodes?.filter { $0.debugName == "dynamic" }.forEach {  control in
        self.validator.unregisterField(control as! ValidatableField)
    }

[RajatJain4061]

@Mammadbayli Your PR is failing 1 check. Can you merge master branch once then push again?