Fix nonce issues when adding product to cart from All Products (https://github.com/woocommerce/woocommerce-blocks/pull/3598)

* Products extend cart route

* load cart in products

plugins/woocommerce-blocks/assets/js/data/shared-controls.js

@@ -55,6 +55,7 @@ export const controls = {
 						} );
 				} )
 				.catch( ( errorResponse ) => {
+					triggerFetch.setNonce( errorResponse.headers );
 					if ( typeof errorResponse.json === 'function' ) {
 						// Parse error response before rejecting it.
 						errorResponse

plugins/woocommerce-blocks/src/StoreApi/Routes/CartCoupons.php

@@ -8,7 +8,7 @@ use Automattic\WooCommerce\Blocks\StoreApi\Utilities\CartController;
  *
  * @internal This API is used internally by Blocks--it is still in flux and may be subject to revisions.
  */
-class CartCoupons extends AbstractRoute {
+class CartCoupons extends AbstractCartRoute {
 	/**
 	 * Get the path of this REST route.
 	 *

plugins/woocommerce-blocks/src/StoreApi/Routes/CartCouponsByCode.php

@@ -8,7 +8,7 @@ use Automattic\WooCommerce\Blocks\StoreApi\Utilities\CartController;
  *
  * @internal This API is used internally by Blocks--it is still in flux and may be subject to revisions.
  */
-class CartCouponsByCode extends AbstractRoute {
+class CartCouponsByCode extends AbstractCartRoute {
 	/**
 	 * Get the path of this REST route.
 	 *

plugins/woocommerce-blocks/src/StoreApi/Routes/CartItemsByKey.php

@@ -8,7 +8,7 @@ use Automattic\WooCommerce\Blocks\StoreApi\Utilities\CartController;
  *
  * @internal This API is used internally by Blocks--it is still in flux and may be subject to revisions.
  */
-class CartItemsByKey extends AbstractRoute {
+class CartItemsByKey extends AbstractCartRoute {
 	/**
 	 * Get the path of this REST route.
 	 *

plugins/woocommerce-blocks/src/StoreApi/Routes/Products.php

@@ -44,6 +44,8 @@ class Products extends AbstractRoute {
 	 * @return \WP_REST_Response
 	 */
 	protected function get_route_response( \WP_REST_Request $request ) {
+		// we load so that we have the same session, this is done so that Add to Cart can function.
+		$this->maybe_load_cart();
 		$response      = new \WP_REST_Response();
 		$product_query = new ProductQuery();