Form group does not create horizontal forms if they are nested

[TimSielemann]

Describe the bug
If you have nested dynamic form elements that are not direct childs of form group, it will not apply the horizontal setting. OnSlotChange seems to only get called when direct childs are changed.

To Reproduce
This will not result in horizontal forms:

<cat-button (catClick)="addInput()">Add Input</cat-button>
<cat-form-group [horizontal]="true">
  <div>
    <div *ngFor="let input of inputs">
      <cat-input label="input"  [formControl]="input"></cat-input>
    </div>
  </div>
</cat-form-group>

Expected behavior
Form elements rendered inside a form group that has horizontal flag will be rendered horizontal.