fix: Arrays returned as objects

[stocaaro]

Description of changes

When customers retrieve models with a.string().array() fields, the content has been repackage as objects.

Testing shows that this doesn't impact direct client.graphql(...) calls.

This change adds a test that fails without the corresponding fix to the flatten logic, correcting it to not translate Array's into Record type objects.

Issue #, if available

• Array of strings is returned as object #12663

Description of how you validated changes

• Manually tested in an app
• Added unit test coverage, confirming repro failure

Checklist

• PR description included
• yarn test passes
• Tests are changed or added

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[svidgen]

Thinking about concern raised OOB

[svidgen]

Meant to flip to not approved while we/I think

[svidgen]

OK. Re-approving. I think this is OK. But, would be great if we could get some test coverage around custom selection set to give us more confidence without the extra manual validation next time these LOC are touched.