smoke-test centroids + graph overlay layer (#1189)

* add test labels

* prettier + add clcik return to clickOn()

* prettier + begin test

* finish label counting test

* add util to get coordinates of element

* add test id to labels

* add test to check overlay transform

* remove logs

* rename to match master

client/src/components/menubar/index.js

@@ -366,6 +366,8 @@ class MenuBar extends React.Component {
           disabled={graphInteractionMode === "zoom"}
         >
           <Button
+            type="button"
+            data-testid="centroid-label-toggle"
             icon="property"
             onClick={this.handleCentroidChange}
             active={showCentroidLabels}