feat: tree-shakeable providers API updates (#22655)

Rename @Injectable({scope -> providedIn}).

Instead of {providedIn: APP_ROOT_SCOPE}, accept {providedIn: 'root'}.
Also, {providedIn: null} implies the injectable should not be added
to any scope.

PR Close #22655

integration/injectable-def/src/lib1.ts

@@ -3,7 +3,7 @@ import {Injectable, NgModule} from '@angular/core';
 @NgModule({})
 export class Lib1Module {}
 
-@Injectable({scope: Lib1Module})
+@Injectable({providedIn: Lib1Module})
 export class Service {
   static instance = 0;
   readonly instance = Service.instance++;