Revert "refactor: optimize plugins for angular treeshaking"

This reverts commit 8b53c04dc5.

src/@ionic-native/plugins/braintree/index.ts

@@ -204,9 +204,7 @@ export interface PaymentUIResult {
     'ionic cordova plugin add https://github.com/taracque/cordova-plugin-braintree',
   installVariables: []
 })
-@Injectable({
-  providedIn: 'root'
-})
+@Injectable()
 export class Braintree extends IonicNativePlugin {
   /**
    * Used to initialize the Braintree client. This function must be called before other methods can be used.