Set the price of a variable product to the minimum price of its variations on Product Feed

[nima-karimi]

The price of the parent variable product must be set to the minimum price of its variations/children. This is how the tracking event is set up, so we should change the feed to be consistent with that:

facebook-for-woocommerce/facebook-commerce-events-tracker.php

Lines 509 to 513 in 28ccf99

	if ( WC_Facebookcommerce_Utils::is_variable_type( $product->get_type() ) ) {
	$product_price = $product->get_variation_price( 'min' );
	} else {
	$product_price = $product->get_price();
	}

We also apply the same idea to other similar product types:

facebook-for-woocommerce/includes/Products.php

Lines 334 to 347 in c034913

	} elseif ( $product->is_type( 'composite' ) ) {
	$price = $product->get_composite_price( 'min', true );
	} elseif ( $product->is_type( 'bundle' ) ) {
	// If product is a product bundle with individually priced items, we rely on their pricing.
	$price = $product->get_bundle_price( 'min', true );
	} elseif ( $product->is_type( 'mix-and-match' ) && is_callable( array( $product, 'get_container_price' ) ) ) {
	// If product is Mix and Match product with individually priced items, we rely on their pricing, since MNM 2.0.
	$price = $product->get_container_price( 'min', true );