14.0.15 breaks nextjs in monorepo

PR https://github.com/FirebaseExtended/firebase-framework-tools/pull/346 breaks nextjs rollouts in a monorepo setup.

We have our next app at `apps/web` and the build output is `apps/web/.next/standalone` but in #346 the adapter only picks root `.next/standalone`.
The build passes successfully but the files are not copied over so the container doesn't run properly and the rollout fails.

The workaround is to add outputFiles manually in apphosting.yml:
```yaml
outputFiles:
serverApp:
include: [.]
```
_the config above copied all files that might make your container to run late for health check, put your real standalone output path instead of ._

14.0.13 was ok