Clarify what "base project directory" means

**Describe the content issue**:
When setting up a new flutter project, there is a directory for the flutter code:

```
myproject/
| - flutter_app/
| - docs/
```

In the docs it refers to "base project directory" which is not explicit. Does this mean inside the `flutter_app/` directory or inside `myproject/` directory?

**URL page where content issue is**:

https://docs.amplify.aws/flutter/start/quickstart/

**Line in docs repo**

https://github.com/aws-amplify/docs/blob/1197ec916b23a7671a0a8955cbfe6e80a29830ab/src/pages/%5Bplatform%5D/start/quickstart/index.mdx?plain=1#L172