Fix Scalar Path generation for queries with inline fragments

[kamilJ96]

If a query contains an inline fragment to select a specific type from a union type, currently the PrepareScalarPaths function will add the inline fragment to the path list. However, when a response is being decoded, this inline fragment is not present on the generated path for a scalar, and so custom scalars can't find their correct decoder.

For e.g:

cards {
  ... on Card {
    info
  }
}

will result in the scalar path being generated as ['Query', 'cards', '... on Card', 'info'], however the response scalar path is generated as ['Query', 'cards', 'info'], as an inline fragment isn't a field