fix(@angular-devkit/build-angular): normalize Vite dev-server Windows asset paths

When using the esbuild-based browser application builder with the Vite-based development
server on Windows, source asset paths were previously not normalized prior to being included
in request URLs. This could result in invalid asset request URLs due to invalid path
segment separators.

(cherry picked from commit a9c6b44)

Author: clydin

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

@@ -267,7 +267,7 @@ export async function setupServer(
             // Rewrite all build assets to a vite raw fs URL
             const assetSourcePath = assets.get(pathname);
             if (assetSourcePath !== undefined) {
-              req.url = `/@fs/${assetSourcePath}`;
+              req.url = `/@fs/${normalizePath(assetSourcePath)}`;
               next();
 
               return;