refactor(@angular-devkit/build-angular): move babel build optimizer plugins from @angular/build

The Babel-based build optimizer plugins ('adjust-static-class-members', 'adjust-typescript-enums', 'elide-angular-metadata', and 'pure-toplevel-functions') are no longer used by '@angular/build', which now uses an OXC-based AST transform for optimization in esbuild.

This change relocates these plugins and their associated unit tests out of '@angular/build' and directly into '@angular-devkit/build-angular', which is their sole remaining consumer.

Moving these plugins also allows removing '@babel/helper-annotate-as-pure' and '@babel/helper-split-export-declaration' as direct dependencies of '@angular/build'.

Author: clydin

packages/angular/build/BUILD.bazel

@@ -82,8 +82,6 @@ ts_project(
         ":node_modules/@angular-devkit/core",
         ":node_modules/@angular/ssr",
         ":node_modules/@babel/core",
-        ":node_modules/@babel/helper-annotate-as-pure",
-        ":node_modules/@babel/helper-split-export-declaration",
         ":node_modules/@inquirer/confirm",
         ":node_modules/@oxc-project/types",
         ":node_modules/@vitejs/plugin-basic-ssl",

packages/angular/build/package.json

@@ -21,8 +21,6 @@
     "@ampproject/remapping": "2.3.0",
     "@angular-devkit/architect": "workspace:0.0.0-EXPERIMENTAL-PLACEHOLDER",
     "@babel/core": "8.0.1",
-    "@babel/helper-annotate-as-pure": "8.0.0",
-    "@babel/helper-split-export-declaration": "7.24.7",
     "@inquirer/confirm": "6.1.1",
     "@vitejs/plugin-basic-ssl": "2.3.0",
     "beasties": "0.4.3",

packages/angular/build/src/private.ts

@@ -32,7 +32,6 @@ export {
 } from './builders/dev-server/options';
 
 // Tools
-export * from './tools/babel/plugins';
 export type { ExternalResultMetadata } from './tools/esbuild/bundler-execution-result';
 export { emitFilesToDisk } from './tools/esbuild/utils';
 export { transformSupportedBrowsersToTargets } from './tools/esbuild/utils';