Fix display of tracker names in solar drilldown pages

- SolarChargers.qml: formatTrackerName() was trying to substitute a
string arg that did not exist
- SolarChargerPage.qml: the QuantityTable needs to ensure the tracker
name is not displayed as an empty string. If the tracker name is
empty, use Global.solarChargers.formatTrackerName() to find an
appropriate name based on the tracker's charger.

data/SolarChargers.qml

@@ -39,7 +39,7 @@ QtObject {
 			if (trackerName.length > 0) {
 				return trackerName
 			} else {
-				return "#%2".arg(deviceName).arg(trackerIndex + 1)
+				return "#%2".arg(trackerIndex + 1)
 			}
 		}
 	}

pages/solar/SolarChargerPage.qml

@@ -71,7 +71,7 @@ Page {
 					valueForModelIndex: function(trackerIndex, column) {
 						const tracker = root.solarCharger.trackers.get(trackerIndex).solarTracker
 						if (column === 0) {
-							return tracker.name
+							return Global.solarChargers.formatTrackerName(tracker.name, trackerIndex, root.solarCharger.trackers.count, root.solarCharger.name, VenusOS.TrackerName_NoDevicePrefix)
 						} else if (column === 1) {
 							// Today's yield for this tracker
 							const history = root.solarCharger.dailyTrackerHistory(0, trackerIndex)