Restore previous Go here map item on cancellation

Added logic to commit and revert coordinate changes for the Go here map
item. Updated the Go To action handlers to utilize this logic, allowing
the previous Go here item to be restored when a Go To action is
cancelled.

Author: rubenp02

src/FlightDisplay/FlyViewMap.qml

@@ -383,18 +383,20 @@ FlightMap {
 
         property bool inGotoFlightMode: _activeVehicle ? _activeVehicle.flightMode === _activeVehicle.gotoFlightMode : false
 
+        property var _committedCoordinate: null
+
         onInGotoFlightModeChanged: {
             if (!inGotoFlightMode && gotoLocationItem.visible) {
                 // Hide goto indicator when vehicle falls out of guided mode
-                gotoLocationItem.visible = false
+                hide()
             }
         }
 
         Connections {
             target: QGroundControl.multiVehicleManager
             function onActiveVehicleChanged(activeVehicle) {
                 if (!activeVehicle) {
-                    gotoLocationItem.visible = false
+                    hide()
                 }
             }
         }
@@ -409,11 +411,29 @@ FlightMap {
         }
 
         function actionConfirmed() {
+            _commitCoordinate()
+
             // We leave the indicator visible. The handling for onInGuidedModeChanged will hide it.
         }
 
         function actionCancelled() {
-            hide()
+            _restoreCoordinate()
+        }
+
+        function _commitCoordinate() {
+            // Must deep copy
+            _committedCoordinate = QtPositioning.coordinate(
+                coordinate.latitude,
+                coordinate.longitude
+            );
+        }
+
+        function _restoreCoordinate() {
+            if (_committedCoordinate) {
+                coordinate = _committedCoordinate
+            } else {
+                hide()
+            }
         }
     }