Assigning the VOD asset id to the copied thumb cuepoint

PLAT-1749 #time 1h
@tan-tan-kanarek The first save() is there in order to generate an ID that is then used for $timedThumbAsset->setCuePointID( $vodThumbCuePoint->getId() ). After that, another save() is called in order to set the newly copied thumb asset id back to the VOD thumb cue point.