For consistency with other Plasma repos, but also to ensure the ECM
logic for supporting uninstalled unit tests is properly triggered
See
https://api.kde.org/ecm/kde-module/KDECMakeSettings.html#build-settings
Including KDECMakeSettings only after finding KF5CoreAddons and the
implicit loading of KF5PlasmaMacros/KF5PackageMacros resets the
ECM_GLOBAL_FIND_VERSION variable to the min ECM value 1.6.0 currently
used by those macro files, thus below the trigger value 5.38