The staging logic will actually take the contents of Engine/Content/Internationalization/InternationalizationPresetName and copy them to Engine/Content/Internationalization/ in the staging directory, which means the icudt53l directory will get “cooked” correctly.
SC.StageFiles(StagedFileType.UFS, CombinePaths(SC.LocalRoot, "Engine", "Content", "Internationalization", InternationalizationPreset), "*", true, null, CombinePaths("Engine", "Content", "Internationalization"), true, !Params.UsePak(SC.StageTargetPlatform));