fix(@angular-devkit/build-angular): retain CSS special comments in global styles

Prior to this change special CSS comments `/*! comment */` were being removed during minification when using the esbuild based builders. This caused tools that ran post build that rely on such comments such as purgeCSS and critters not to function properly.

Closes: angular#26432

Author: alan-agius4

packages/angular_devkit/build_angular/src/builders/application/tests/behavior/stylesheet-special-comments_spec.ts

@@ -0,0 +1,39 @@
+/**
+ * @license
+ * Copyright Google LLC All Rights Reserved.
+ *
+ * Use of this source code is governed by an MIT-style license that can be
+ * found in the LICENSE file at https://angular.io/license
+ */
+
+import { buildApplication } from '../../index';
+import { APPLICATION_BUILDER_INFO, BASE_OPTIONS, describeBuilder } from '../setup';
+
+describeBuilder(buildApplication, APPLICATION_BUILDER_INFO, (harness) => {
+  describe('Behavior: "Stylesheet special comments"', () => {
+    it(`should retain special comments when minification is enabled`, async () => {
+      await harness.writeFile(
+        'src/styles.css',
+        `
+          /* normal-comment */
+          /*! important-comment */
+          div { flex: 1 }
+        `,
+      );
+
+      harness.useTarget('build', {
+        ...BASE_OPTIONS,
+        optimization: true,
+        extractLicenses: true,
+        styles: ['src/styles.css'],
+      });
+
+      const { result } = await harness.executeOnce();
+      expect(result?.success).toBeTrue();
+
+      harness
+        .expectFile('dist/browser/styles.css')
+        .content.toMatch(/\/\*! important-comment \*\/[\s\S]*div{flex:1}/);
+    });
+  });
+});

packages/angular_devkit/build_angular/src/tools/esbuild/global-styles.ts

@@ -65,7 +65,10 @@ export function createGlobalStylesBundleOptions(
       },
       loadCache,
     );
-    buildOptions.legalComments = options.extractLicenses ? 'none' : 'eof';
+
+    // Keep special CSS comments `/*! comment */` in place.
+    // These comments are special for a number of CSS tools such as Critters and PurgeCSS.
+    buildOptions.legalComments = 'inline';
     buildOptions.entryPoints = entryPoints;
 
     buildOptions.plugins.unshift(