EntityCreateAccessCheck should support default route parameters

This is a follow up to  #2743303-22: EntityForm::getEntityFromRouteMatch() does not support route-level parameters.

Problem/Motivation

We recently changed from using _node_add_access which made me realize that _entity_create_access won't take a default parameter.

Steps to reproduce

Add a route that uses a default instead of a path slug.

my.node.add:
  path: '/my/node/add/page'
  defaults:
    node_type: 'page'
    _entity_form: 'node.default'
    _title_callback: '\Drupal\node\Controller\NodeController::addPageTitle'
  requirements:
    _entity_create_access: 'node:{node_type}'
  options:
    _node_operation_route: TRUE
    parameters:
      node_type:
        type: entity:node_type

When you load the page you should get a 403 Access denied. After applying the patch you should no longer get a 403, but get an error "The website encountered an unexpected error. Please try again later." which applying the patch from #2743303-22: EntityForm::getEntityFromRouteMatch() does not support route-level parameters will fix.

Proposed resolution

Let's call $route_match->getParameters() instead of getRawParameters(). getParameters() resolves default route parameters for us. The description of the related issue says that

Using $route_match->getRawParameter() is needed because some parameters are likely to be upcasted

We can just get the ID of the parameter in that case and support default parameters.