fix flow type for nestedPath

[gyDBD]

Issue:

codegen generate wrong flow type when I use nestedPath.

dataloader-config.yaml

   getFilmsV2:
        docsLink: https://swapi.dev/documentation#films
        isBatchResource: true
        batchKey: film_ids
        newKey: film_id
        nestedPath: properties

Status Quo

The flow type of response is any, which is wrong!

after my change in src/genTypeFlow.ts

We get the correct flow type.

What's wrong?

If the response is nested in some path, we need to first unwrap it. Then if it's a batch resource, we do $ElementType<${retVal}, 0> The order of two if-else statement matters!

Test Done

make test passed
Also see my swapi example ^ (screen shot above)

[magicmark]

nice!