A CanLoad guard returning UrlTree cancels current navigation and redirects.
This matches the behavior available to `CanActivate` guards added in #26521.
Note that this does not affect preloading. A `CanLoad` guard blocks any
preloading. That is, any route with a `CanLoad` guard is not preloaded
and the guards are not executed as part of preloading.
fixes#28306
PR Close#36610