Hi! I am trying to label line features in the ArcGIS Online Map Viewer and I don't see the label placement property in the label style dialogue box. I am expecting to see it where I have added the pink squiggly line in the image below.

The layer in question is a registered service, where the URL is "....mapserver/0" so it is registered as a feature layer.
Below is the same data registered as a map image layer where I see the property I need (but I don't want the layer to be registered as a map image layer but a feature layer):
