Symfony API loader do not consider route priority

**API Platform version(s) affected**: 4.0

**Description**  

ApiLoader Routing service does not consider route priority set in operation configuration


**Possible Solution**  
Replace

` $routeCollection->add($operationName, $route);
`

 to 
 
`$routeCollection->add($operationName, $route, $operation->getPriority() ?? 0);
`