refactor(@schematics/angular): move standalone component helpers to a private export for Angular components

The standalone component helper utilities introduced into the `@angular/cdk` via
angular/components#24931 have been added to an export path (`private/components`)
within `@schematics/angular`. The export path is primarily intended for the use of the components schematics
within `@angular/cdk` and `@angular/material`. The API exported from this path is not considered public API,
does not provide SemVer guarantees, and may be modified or removed without a deprecation cycle.

Author: clydin

packages/schematics/angular/package.json

@@ -13,7 +13,8 @@
     "./utility": "./utility/index.js",
     "./utility/*": "./utility/*.js",
     "./migrations/migration-collection.json": "./migrations/migration-collection.json",
-    "./*": "./*.js"
+    "./*": "./*.js",
+    "./private/components": "./private/components.js"
   },
   "schematics": "./collection.json",
   "dependencies": {