Explicit 3rd parameter doesn't override default behavior which declared in toasrConfig file

My toastrConfig.ts has 

```
export function toastrConfig(toastrConfig: any): void {
 ...
  toastrConfig.positionClass = 'toast-top-right';
...
}
```

but for one my particular case I just want to show toastr bottom-right:

```
toastr.info('<input type="checkbox" checked> Success!', 'With HTML', {
  positionClass: 'toast-bottom-right';
});
```

but toasts still show on top right