Build react-server-dom-webpack for codesandbox (#32990)

This allows us to test Flight changes in a codesandbox.

[Example](https://codesandbox.io/p/devbox/zkjk7y)

Author: unstubbable

.codesandbox/ci.json

@@ -1,10 +1,11 @@
 {
-  "packages": ["packages/react", "packages/react-dom", "packages/scheduler"],
+  "packages": ["packages/react", "packages/react-dom", "packages/react-server-dom-webpack", "packages/scheduler"],
   "buildCommand": "download-build-in-codesandbox-ci",
   "node": "18",
   "publishDirectory": {
     "react": "build/oss-experimental/react",
     "react-dom": "build/oss-experimental/react-dom",
+    "react-server-dom-webpack": "build/oss-experimental/react-server-dom-webpack",
     "scheduler": "build/oss-experimental/scheduler"
   },
   "sandboxes": ["new"],

package.json

@@ -146,7 +146,7 @@
     "publish-prereleases": "echo 'This command has been deprecated. Please refer to https://github.com/facebook/react/tree/main/scripts/release#trigger-an-automated-prerelease'",
     "download-build": "node ./scripts/release/download-experimental-build.js",
     "download-build-for-head": "node ./scripts/release/download-experimental-build.js --commit=$(git rev-parse HEAD)",
-    "download-build-in-codesandbox-ci": "yarn build --type=node react/index react-dom/index react-dom/client react-dom/src/server react-dom/test-utils scheduler/index react/jsx-runtime react/jsx-dev-runtime",
+    "download-build-in-codesandbox-ci": "yarn build --type=node react/index react.react-server react-dom/index react-dom/client react-dom/src/server react-dom/test-utils react-dom.react-server scheduler/index react/jsx-runtime react/jsx-dev-runtime react-server-dom-webpack",
     "check-release-dependencies": "node ./scripts/release/check-release-dependencies",
     "generate-inline-fizz-runtime": "node ./scripts/rollup/generate-inline-fizz-runtime.js",
     "flags": "node ./scripts/flags/flags.js"