fix(router): Add missing dependency for RSC

[Tobbe]

Adding missing dependency react-server-dom-webpack to the @redwoodjs/router package. This should hopefully fix the following error some users have been seeing when trying to try out RSC:

node:internal/process/promises:391
    triggerUncaughtException(err, true /* fromPromise */);
    ^

[vite]: Rollup failed to resolve import "react-server-dom-webpack/client" from "/Users/tobbe/tmp/rw-rsc-long-way/node_modules/@redwoodjs/router/dist/rsc/RscRoutes.js".
This is most likely unintended because it can break your application at runtime.
If you do want to externalize this module explicitly add it to
`build.rollupOptions.external`
    at viteWarn (file:///Users/tobbe/tmp/rw-rsc-long-way/node_modules/vite/dist/node/chunks/dep-CUvs3bbV.js:65528:17)

react-server-dom-webpack is already a dependency of @redwoodjs/vite, but when I moved things from the vite package over to the router package I forgot to also copy over this dependency.

This mostly affects the experimental RSC feature. But because everyone will get the new dependency installed I didn't mark the PR with the "experimental" label