[EventDelegate] Hide location name if there is none

Avoids an awkward gap

src/app/EventDelegate.qml

@@ -43,6 +43,7 @@ App.TimelineDelegate {
 
         QQC2.Label {
             text: reservationFor.location != undefined ? reservationFor.location.name : ""
+            visible: text !== ""
             wrapMode: Text.WordWrap
             width: topLayout.width
         }