chore: remove empty builder.buildApp for cloudflare

Author: hi-ogawa

packages/plugin-rsc/examples/starter-cf-single/vite.config.ts

@@ -50,12 +50,4 @@ export default defineConfig({
       },
     },
   },
-  builder: {
-    // empty buildApp to disable cloudflare's buildApp
-    // https://github.com/cloudflare/workers-sdk/blob/19e2aab1d68594c7289d0aa16474544919fd5b9b/packages/vite-plugin-cloudflare/src/index.ts#L183-L186
-    buildApp: async () => {},
-  },
-  rsc: {
-    serverHandler: false,
-  },
 })