Reload on global fetch event and emit vis:ready (#12805)

this  fixes 
- the issue where adding a saved search panel after adding a visualization, would cause the panel to remain empty.
- clicking the magnifier glass int he query-bar on the dashboard page not refreshes the visualization

src/ui/public/visualize/visualize.js

@@ -88,7 +88,8 @@ uiModules
         $scope.fetch();
       };
       $scope.vis.on('reload', reload);
-      $scope.$on('courier:searchRefresh', reload);
+      // dashboard will fire fetch event when it wants to refresh
+      $scope.$on('fetch', reload);
 
       if ($scope.appState) {
         let oldUiState;
@@ -135,6 +136,7 @@ uiModules
       });
 
       $scope.fetch();
+      $scope.$root.$broadcast('ready:vis');
     }
   };
 });