test(cli): add monorepo e2e test based on a custom fixture

[byCedric]

Why

This is a draft to add a specific monorepo test to the exporting e2e tests.

How

• We need a custom fixture for this, so I added one based on e2e/fixtures/with-router
• Add a single test case that checks if both projects are not leaking code, based on static routes

Test Plan

• Test without the fix is confirmed failing in: https://github.com/expo/expo/actions/runs/9499559787/job/26180698726?pr=29735#step:10:115
• When rebasing on the fix from fix(metro-config): add _expoRelativeProjectRoot to invalidate Metro cache within monorepos #29733, it should work

Checklist

• Documentation is up to date to reflect these changes (eg: https://docs.expo.dev and README.md).
• Conforms with the Documentation Writing Style Guide
• This diff will work correctly for npx expo prebuild & EAS Build (eg: updated a module plugin).

[byCedric]

Ah yeah, the fixture is not connected to the source code, hence it's still failing.

[expo-bot]

Hi there! 👋 I'm a bot whose goal is to ensure your contributions meet our guidelines.

I've found some issues in your pull request that should be addressed (click on them for more details) 👇

⚠️ Suggestion: Missing changelog entries

Your changes should be noted in the changelog. Read Updating Changelogs guide and consider adding an appropriate entry to the following changelogs:

• packages/@expo/cli/CHANGELOG.md

---

Generated by ExpoBot 🤖 against 7c07448