refactor: 💡 ServicesManager factory functions vs instances (#1272)

* refactor: 💡 ServicesManager factory functions vs instances

Refactor servicesManager to take factory functions instead of instances

Closes: #1265

* Remove testing code

platform/viewer/src/App.js

@@ -28,11 +28,11 @@ import {
   ExtensionManager,
   ServicesManager,
   HotkeysManager,
-  createUINotificationService,
-  createUIModalService,
-  createUIDialogService,
-  createUIContextMenuService,
-  createUILabellingFlowService,
+  UINotificationService,
+  UIModalService,
+  UIDialogService,
+  UIContextMenuService,
+  UILabellingFlowService,
   utils,
   redux as reduxOHIF,
 } from '@ohif/core';
@@ -70,13 +70,6 @@ const commandsManagerConfig = {
   getActiveContexts: () => getActiveContexts(store.getState()),
 };
 
-/** Services */
-const UINotificationService = createUINotificationService();
-const UIModalService = createUIModalService();
-const UIDialogService = createUIDialogService();
-const UIContextMenuService = createUIContextMenuService();
-const UILabellingFlowService = createUILabellingFlowService();
-
 /** Managers */
 const commandsManager = new CommandsManager(commandsManagerConfig);
 const hotkeysManager = new HotkeysManager(commandsManager);
@@ -165,6 +158,14 @@ class App extends Component {
 
   render() {
     const { whiteLabelling, routerBasename } = this._appConfig;
+    const {
+      UINotificationService,
+      UIDialogService,
+      UILabellingFlowService,
+      UIModalService,
+      UIContextMenuService,
+    } = servicesManager.services;
+
     if (this._userManager) {
       return (
         <AppContext.Provider value={{ appConfig: this._appConfig }}>