fix: improper cloning of custom fields

[shmishtopher]

Fixes a bug where MetaObjectField passes custom fields into the constructor after calling clone, causing the editor to crash due to missing .get() methods on the custom fields.

[aarthificial]

I believe this.transform('get') should also include customFields, just like how serialize does.

[shmishtopher]

I'm not sure how much sense it makes to include custom fields in the transform itself, given that any calls to get on custom fields would fail anyway. I added an override to the ObjectMetaField::get method in the latest commit as a workaround. Alternatively, we can return to your original implementation of ObjectMetaField::transform and add special handling to the ObjectMetaField constructor to fix the erroneous calls to get.

[aarthificial]

Apologies for the confusion. I meant that the place where this.transform('get') is invoked (in the handleChange callback) should include customFields. This is where the value is calculated and so corresponding calls to get would return it too:

protected handleChange = () => {
  if (this.ignoreChange) return;
  this.value.current = {
    ...this.transform('get'),
    ...this.customFields,
  };
};

[aarthificial]

Awesome, thanks for the fix!