Given the active client has set a display config, when a hardware change occurs we rely on the client to update the config

Given the active client has set a display config, when a hardware change occurs we rely on the client to update the config

For example, unplugging the only active display won't reconfigure the display until a session switch or the active client applying a new display config.

C.f. NestedServer.DISABLED_given_client_set_display_configuration_when_monitor_unplugs_configuration_is_reset

We should probably allow the client time to apply a configuration (to avoid possibly redundant configuration changes and reduce flickering), but not rely on that happening.