Cluster receiver configuration not present by default in Flutter cluster demo image

The cluster-receiver package is present in agl-cluster-demo-platform-flutter by default since 34fd1612, but that change tied the geometry configuration for the receiver to fit on top of the Flutter cluster app to the agl-demo-preload feature.  That results in the receiver covering up some of the gauges area in default builds, which seems less than ideal for the out of the box experience.  Since we are not likely to pull the cluster-receiver back out and fix up the Flutter navigation code (switching to something Toyota provides support for seems more likely), then fixing this for the short to mid term seems worthwhile.