🐛 BUG: React Router template config uses outdated object key

### Which template does this pertain to?

react-router-starter-template

### What versions are you using?

Latest template

### What operating system and version are you using?

macOS Tahoe

### Please provide a link to a minimal reproduction (optional)

_No response_

### Describe the Bug

Running `pnpm run dev` results in the following error: `Error: The "future.unstable_viteEnvironmentApi" flag has been stabilized as "future.v8_viteEnvironmentApi"` due to the usage of an outdated config object key.

PR incoming.

### Please provide any relevant error logs

_No response_