Don't immediately create app.json when running eas in an unconfigured directory

### Minimal reproducible example

Shouldn't have to clean up a file when mistakenly running the command in the wrong dir. Thanks!

### Steps to reproduce

- run `eas *` in a non-eas directory
- observe `app.json` created

### Environment

```text
npmGlobalPackages:
eas-cli: 16.6.2
```

### Expo Doctor Diagnostics

```text
-
```