Remove default `_locale` parameter in AdminRouteGenerator

[andersonamuller]

It is overriding the selected route locale in localized routes.

Fix #6842

I tried to add a new dashboard in EasyCorp\Bundle\EasyAdminBundle\Tests\PrettyUrlsTestApplication\Controller with localized routes, but still, couldn't make it so easy to test it. Any tips?

[Dallas62]

Please, check the impact before merging: https://github.com/EasyCorp/EasyAdminBundle/pull/6754

[andersonamuller]

Any idea how we can move this forward? This is currently our only blocker to switch to pretty URLs as defining the _locale on route default, prevent the router to generate localized routes for the standard CRUD actions.

The fact the custom actions on CRUD controllers and routes using the #[AdminRoute] attribute don't suffer with the problem makes it more likely that the original fix for https://github.com/EasyCorp/EasyAdminBundle/pull/6754 was not the correct one, otherwise it should have been applied to custom routes as well.