fix some tests

plugins/API/tests/Unit/WidgetMetadataTest.php

plugins/AnonymousPiwikUsageMeasurement

...Visualizations/tests/Integration/SparklinesConfigTest.php

plugins/VisitFrequency/Reports/Get.php

...est_sortByProcessedMetric__API.getProcessedReport_day.xml

.../test_apiGetReportMetadata__API.getReportMetadata_day.xml

...test_apiGetReportMetadata__API.getReportPagesMetadata.xml

...ed/test_apiGetReportMetadata__API.getSegmentsMetadata.xml

...cted/test_apiGetReportMetadata__API.getWidgetMetadata.xml

tests/UI/expected-ui-screenshots