Fix filtering by product type on Store API (#4422)

* Fixed $tax_query being set to an empty array

* Remove whitespace causing PHP coding standards test to fail

* Cleanup: add line break

Co-authored-by: Michael P. Pfeiffer <frontdevde@users.noreply.github.com>

src/StoreApi/Utilities/ProductQuery.php

@@ -41,6 +41,9 @@ public function prepare_objects_query( $request ) {
 			$args['post_type'] = [ 'product', 'product_variation' ];
 		}
 
+		// Taxonomy query to filter products by type, category, tag, shipping class, and attribute.
+		$tax_query = [];
+
 		// Filter product type by slug.
 		if ( ! empty( $request['type'] ) ) {
 			if ( 'variation' === $request['type'] ) {
@@ -88,9 +91,6 @@ public function prepare_objects_query( $request ) {
 			}
 		}
 
-		// Taxonomy query to filter products by type, category, tag, shipping class, and attribute.
-		$tax_query = [];
-
 		$operator_mapping = [
 			'in'     => 'IN',
 			'not_in' => 'NOT IN',