fix(@angular-devkit/build-angular): issue dev-server support warning …

…when using esbuild builder

The dev-server builder currently does not support the experimental esbuild-based browser application
builder and will use the Webpack-based builder instead. To better inform users of this behavior, a
warning is now issued upon executing the dev-server.

(cherry picked from commit 0fcc603)

packages/angular_devkit/build_angular/src/builders/dev-server/index.ts

@@ -141,6 +141,16 @@ export function serveWebpackBrowser(
     const cacheOptions = normalizeCacheOptions(metadata, context.workspaceRoot);
 
     const browserName = await context.getBuilderNameForTarget(browserTarget);
+
+    // Issue a warning that the dev-server does not currently support the experimental esbuild-
+    // based builder and will use Webpack.
+    if (browserName === '@angular-devkit/build-angular:browser-esbuild') {
+      logger.warn(
+        'WARNING: The experimental esbuild-based builder is not currently supported ' +
+          'by the dev-server. The stable Webpack-based builder will be used instead.',
+      );
+    }
+
     const browserOptions = (await context.validateOptions(
       {
         ...rawBrowserOptions,