Steps to reproduce:

1. Create new Content Type (identifier "matrix") with ezmatrix fieldtype (identifier "matrix") - add one row with "one" as the name and "one" as the identifier.
2. Regenerate GraphQL schema with the ibexa:graphql:generate-schema command.
3. Create new content out of the Content Type.
4. Query it in GraphQL:

   {
     content {
       matrixes(first: 1) {
         edges {
           node {
             matrix {
               one
             }
           }
         }
       }
     }
   }
   

Result:
One is presented with an exception:

Fatal Error in GraphQL, caused by incorrect type definition in ProductCatalog bundle:
Ibexa\\ProductCatalog\\GraphQL\\Resolver\\MatrixFieldType
FieldValueResolver::resolveMatrixFieldValue(): Argument #1 ($product) must be of type Ibexa\\Contracts\\ProductCatalog\\Values
ProductInterface, Ibexa\\GraphQL\\Value
Item given, called in /app/vendor/overblog/graphql-bundle/src/Resolver/AbstractProxyResolver.php on line 36

Expected result:
Query should be completed without any issue.