Incorrect implementation of ModuleUninstallValidatorInterface::validate

Problem/Motivation

In some exotic cases a module can be installed and uninstalled in a span of a single site-install process.
MenuItemExtrasUninstallValidator::validate reacts to this event and produces results mismatching expected behaviour(does not return a travesable result), which leads to a warning during the tests setup process.

Steps to reproduce

Manually install a module that isn't in a core.extension config, e.g. using module_installer service during the install hook of some other module.