Revert "refactor: use new Http library in playground (#29355)"

This reverts commit acfcf90528.

modules/playground/src/jsonp/index.ts

@@ -6,18 +6,14 @@
  * found in the LICENSE file at https://angular.io/license
  */
 
-import {HttpClientJsonpModule, HttpClientModule} from '@angular/common/http';
 import {NgModule} from '@angular/core';
+import {JsonpModule} from '@angular/http';
 import {BrowserModule} from '@angular/platform-browser';
 import {platformBrowserDynamic} from '@angular/platform-browser-dynamic';
 
 import {JsonpCmp} from './app/jsonp_comp';
 
-@NgModule({
-  bootstrap: [JsonpCmp],
-  declarations: [JsonpCmp],
-  imports: [BrowserModule, HttpClientModule, HttpClientJsonpModule]
-})
+@NgModule({bootstrap: [JsonpCmp], declarations: [JsonpCmp], imports: [BrowserModule, JsonpModule]})
 export class ExampleModule {
 }