Changes proposed in this Pull Request:

Ref: p1724235667349019/1722414955.111429-slack-C02BB3F30TG

Reverts #2519

This PR fixes an error introduced in #2519

At first, I understood that it was expected to get all empty props as an empty object. However, what was expected was only to get the Settings prop as an object. Rest of the props should be as before.

This PR reverts #2519 and makes only settings to be returned as an object.

Screenshots:

Detailed test instructions:

1. Checkout this PR and
2. Request wp-json/wc/v3/products?gla_syncable=1
3. attributes field is shown as an array (when is empty and when is filled)
4. gla_attributes field is shown as an object (when is empty and when is filled)
5. Request wp-json/wc/v3/settings/general?gla_syncable=1
6. settings field is shown as an object (when is empty and when is filled)
7. Add the following filter which will return empty settings for the flat shipping rate:

add_filter(
	'woocommerce_shipping_instance_form_fields_flat_rate',
	function ( $defaults ) {
		return [];
	},
	10,
	1
);

6. Make a request to v3/shipping/zones/YOUR_SHIPPING_ZONE/methods?gla_syncable=1 which includes a Flat Rate method.
7. See the response:

Before:

After

Additional details:

Changelog entry