build: create integration test for ng-update migrations (#32349)

Creates anew integratin test for `ng-update` migrations. The
integration test uses an Angular CLI project that will be updated
using the latest package output symlinked from then `./dist/packages-dist`.

This allows us to ensure that migrations work in real CLI projects.
Another big benefit is that the Angular version is updated to the
latest. This is something we couldn't replicate in unit tests but
is extremely important. It's important because compilation could
break with newer Angular versions (note that migrations are always
executed after the new angular version has been installed).

PR Close #32349

integration/ng_update_migrations/src/environments/environment.prod.ts

@@ -0,0 +1,3 @@
+export const environment = {
+  production: true
+};

integration/ng_update_migrations/src/environments/environment.ts

@@ -0,0 +1,16 @@
+// This file can be replaced during build by using the `fileReplacements` array.
+// `ng build --prod` replaces `environment.ts` with `environment.prod.ts`.
+// The list of file replacements can be found in `angular.json`.
+
+export const environment = {
+  production: false
+};
+
+/*
+ * For easier debugging in development mode, you can import the following file
+ * to ignore zone related error stack frames such as `zone.run`, `zoneDelegate.invokeTask`.
+ *
+ * This import should be commented out in production mode because it will have a negative impact
+ * on performance if an error is thrown.
+ */
+// import 'zone.js/dist/zone-error';  // Included with Angular CLI.