tests:effect: Do not re-add effect to the track
tests:effect: Do not re-add effect to the track

pitivi/gst-editing-services,cfoch/ges,pitivi/gst-editing-services,cfoch/ges,cfoch/ges,cfoch/gst-editing-services,cfoch/gst-editing-services,cfoch/gst-editing-services,pitivi/gst-editing-services,pitivi/gst-editing-services,cfoch/ges,cfoch/gst-editing-services