Disabled FormControls are enabled on form creation

[JoschuaSchneider]

While working on the issue I mentioned in #303 we found another Problem when creating disabled controls.

When passing a disabled control like this:

public form = createForm<MyForm>({
  ...,
  formControls: {
    name: new FormControl({ value: '', disabled: true }),
  }
});

The FormGroup that the name control is added to is being set to "enabled" because the disabled$ observable is defaulted to of(false) which causes the formGroup.enable call here:
https://github.com/cloudnc/ngx-sub-form/blob/43dede0015975db59333abbc185964a15acb4262/projects/ngx-sub-form/src/lib/create-form.ts#L238C13-L238C13

This resets all disabled states that I initially pass to the FormControls.

I found two workarounds:

1. Provide disabled$ as a never emitting observable:

public form = createForm<MyForm>({
  ...,
  disabled$: new Observable<boolean>(),
  formControls: {
    name: new FormControl({ value: '', disabled: true }),
  }
});

2. Set the disabled state again in the constructor:

constructor() {
  this.form.formGroup.controls.name.disable();
}

This behaviour was unexpected as the new API also handles the default values via the FormControl constructors.