fix(@angular/build): automatically resolve .mjs files when using Vite

Previously, ESM file resolution without extensions failed when using Vite, causing issues in module loading. This commit addresses the problem by automatically resolving `.mjs` files, aligning the behavior with the application builder and ensuring consistent module resolution across different build tools.

**NB**:  This is a workaround as valid ESM imports should always have an extension.

Closes #27841

(cherry picked from commit 2324d5a)

packages/angular/build/src/builders/dev-server/vite-server.ts

@@ -675,6 +675,7 @@ function getDepOptimizationConfig({
  supported: getFeatureSupport(target, zoneless),
  plugins,
  loader,
+ resolveExtensions: ['.mjs', '.js', '.cjs'],
  },
  };
 }

packages/angular/build/src/tools/esbuild/application-code-bundle.ts

@@ -360,7 +360,7 @@ function getEsBuildCommonOptions(options: NormalizedApplicationBuildOptions): Bu
  format: 'esm',
  assetNames: outputNames.media,
  conditions: ['es2020', 'es2015', 'module'],
- resolveExtensions: ['.ts', '.tsx', '.mjs', '.js'],
+ resolveExtensions: ['.ts', '.tsx', '.mjs', '.js', '.cjs'],
  metafile: true,
  legalComments: options.extractLicenses ? 'none' : 'eof',
  logLevel: options.verbose && !jsonLogs ? 'debug' : 'silent',

packages/angular/build/src/tools/esbuild/global-scripts.ts

@@ -63,7 +63,7 @@ export function createGlobalScriptsBundleOptions(
  assetNames: outputNames.media,
  mainFields: ['script', 'browser', 'main'],
  conditions: ['script'],
- resolveExtensions: ['.mjs', '.js'],
+ resolveExtensions: ['.mjs', '.js', '.cjs'],
  logLevel: options.verbose && !jsonLogs ? 'debug' : 'silent',
  metafile: true,
  minify: optimizationOptions.scripts,