Values are not converted to their original types on server

[ochicf]

When performing a mutation that includes a File, the graphql request is done with multipart/form-data content type header (instead of application/json). That causes all the data to be received as string, losing the original data type.

Fields at root level of a collection are properly casted back (I don't know why nor where), but it does not happen with nested fields. That causes that all data in nested fields is not being saved properly, and can trigger validation errors (of type errors.expectedType).

More investigation should be performed in order to:

• know why and where root fields are properly casted
• try to cast nested fields there, or decide a good place where it can be done