fixup! feat(@angular/build): add library builder

Author: alan-agius4

packages/angular/build/src/builders/library/pipeline/bundler.ts

@@ -214,7 +214,7 @@ function createMemoryFileLoaderPlugin(
           return { id: resolvedCandidate, external: false };
         }
 
-        return { id, external: true };
+        return undefined;
       },
     },
     load(id) {

packages/angular/build/src/builders/library/tests/setup.ts

@@ -6,7 +6,7 @@
  * found in the LICENSE file at https://angular.dev/license
  */
 
-import { BuilderHandlerFn } from '@angular-devkit/architect';
+import type { BuilderHandlerFn } from '@angular-devkit/architect';
 import { TestProjectHost } from '@angular-devkit/architect/testing';
 import { json, normalize, join } from '@angular-devkit/core';
 import { readFileSync } from 'node:fs';