Issue #3593114 by mably: Inline enable/disable action targets the requested domain, not the active editing domain

Fixes #3593114.

The inline enable/disable link (domain_config_ui.inline_action) runs on its own request. The editing domain that drove the config form (for example a domain_config_switcher URL-query selection) is not re-established on that request, so the controller's getActiveEditingDomainId() === $domain_id check resolved the active editing domain to the negotiated (current) domain and rejected any other domain with a "Bad request." message.

This validates that the requested domain exists and acts on the domain id from the route instead. The route already authorizes the action through its _csrf_token requirement (bound to the exact op/domain/config path) and the administer domain config ui permission, so trusting the requested domain id is safe.

Adds a kernel test (DomainConfigInlineActionTest) that enables an override for a domain that is not the active editing domain. It fails before this change and passes after.