dashboard: Close/hide 'Add Panel' before saving a dashboard (#10482)

Fixes #10472

public/app/features/dashboard/dashboard_model.ts

@@ -145,7 +145,10 @@ export class DashboardModel {
     };
 
     // get panel save models
-    copy.panels = _.map(this.panels, panel => panel.getSaveModel());
+    copy.panels = _.chain(this.panels)
+      .filter(panel => panel.type !== 'add-panel')
+      .map(panel => panel.getSaveModel())
+      .value();
 
     //  sort by keys
     copy = sortByKeys(copy);

public/app/features/dashboard/specs/dashboard_model.jest.ts

@@ -49,6 +49,23 @@ describe('DashboardModel', function() {
       expect(keys[0]).toBe('annotations');
       expect(keys[1]).toBe('autoUpdate');
     });
+
+    it('should remove add panel panels', () => {
+      var model = new DashboardModel({});
+      model.addPanel({
+        type: 'add-panel',
+      });
+      model.addPanel({
+        type: 'graph',
+      });
+      model.addPanel({
+        type: 'add-panel',
+      });
+      var saveModel = model.getSaveModelClone();
+      var panels = saveModel.panels;
+
+      expect(panels.length).toBe(1);
+    });
   });
 
   describe('row and panel manipulation', function() {