loadMeasurements: fix bug for warning notifications

Fix bug where the warning notification for measurements JSON was being
fired even when the dataset did not request the measurements panel.

Based on feedback from @jameshadfield
<#1881 (comment)>

src/actions/measurements.js

@@ -279,11 +279,13 @@ const parseMeasurementsJSON = (json) => {
 
 export const loadMeasurements = (measurementsData, dispatch) => {
   let measurementState = getDefaultMeasurementsState();
+  /* Just return default state there are no measurements data to load */
+  if (!measurementsData) {
+    return measurementState
+  }
+
   let warningMessage = "";
-  if (measurementsData === undefined) {
-    // eslint-disable-next-line no-console
-    console.debug("No measurements JSON fetched");
-  } else if (measurementsData instanceof Error) {
+  if (measurementsData instanceof Error) {
     console.error(measurementsData);
     warningMessage = "Failed to fetch measurements collections";
   } else {