refactor(@schematics/angular): add trailing comma to generated services

Ensures code consistency by including trailing commas in generated service

(cherry picked from commit 6dfee71)

Author: MeAkib

packages/schematics/angular/service/files/__name@dasherize__.__type@dasherize__.ts.template

@@ -1,7 +1,7 @@
 import { Injectable } from '@angular/core';
 
 @Injectable({
-  providedIn: 'root'
+  providedIn: 'root',
 })
 export class <%= classify(name) %><%= classify(type) %> {
 

packages/schematics/angular/service/index_spec.ts

@@ -55,7 +55,7 @@ describe('Service Schematic', () => {
 
     const tree = await schematicRunner.runSchematic('service', options, appTree);
     const content = tree.readContent('/projects/bar/src/app/foo/foo.ts');
-    expect(content).toMatch(/providedIn: 'root'/);
+    expect(content).toMatch(/providedIn: 'root',/);
   });
 
   it('should respect the skipTests flag', async () => {