refactor(ivy): generate ngFactoryDef for injectables (#32433)

With #31953 we moved the factories for components, directives and pipes into a new field called `ngFactoryDef`, however I decided not to do it for injectables, because they needed some extra logic. These changes set up the `ngFactoryDef` for injectables as well.

For reference, the extra logic mentioned above is that for injectables we have two code paths:

1. For injectables that don't configure how they should be instantiated, we create a `factory` that proxies to `ngFactoryDef`:

```
// Source
@Injectable()
class Service {}

// Output
class Service {
  static ngInjectableDef = defineInjectable({
    factory: () => Service.ngFactoryFn(),
  });

  static ngFactoryFn: (t) => new (t || Service)();
}
```

2. For injectables that do configure how they're created, we keep the `ngFactoryDef` and generate the factory based on the metadata:

```
// Source
@Injectable({
  useValue: DEFAULT_IMPL,
})
class Service {}

// Output
export class Service {
  static ngInjectableDef = defineInjectable({
    factory: () => DEFAULT_IMPL,
  });

  static ngFactoryFn: (t) => new (t || Service)();
}
```

PR Close #32433

packages/core/test/acceptance/di_spec.ts

@@ -951,6 +951,37 @@ describe('di', () => {
             `This will become an error in v10. Please add @Injectable() to the "SubSubClass" class.`);
       }
     });
+
+    it('should instantiate correct class when undecorated class extends an injectable', () => {
+      @Injectable()
+      class MyService {
+        id = 1;
+      }
+
+      class MyRootService extends MyService {
+        id = 2;
+      }
+
+      @Component({template: ''})
+      class App {
+      }
+
+      TestBed.configureTestingModule({declarations: [App], providers: [MyRootService]});
+      const warnSpy = spyOn(console, 'warn');
+      const fixture = TestBed.createComponent(App);
+      fixture.detectChanges();
+
+      const provider = TestBed.inject(MyRootService);
+
+      expect(provider instanceof MyRootService).toBe(true);
+      expect(provider.id).toBe(2);
+
+      if (ivyEnabled) {
+        expect(warnSpy).toHaveBeenCalledWith(
+            `DEPRECATED: DI is instantiating a token "MyRootService" that inherits its @Injectable decorator but does not provide one itself.\n` +
+            `This will become an error in v10. Please add @Injectable() to the "MyRootService" class.`);
+      }
+    });
   });
 
   describe('inject', () => {