Column preset restricts column access in mutation for configured role

**Background:** The [docs ](https://hasura.io/docs/1.0/graphql/manual/schema/default-values/column-presets.html) say:
> If a column has a preset defined for a given role, access to the column for mutations will be restricted for users with that role.

**Problem:** The client must make sure that, depending on the role and its permissions in hasura, the column with a preset defined must not be delivered with the mutation (not even as `undefined`). This makes the client tightly coupled to the hasura permissions schema.

**Idea:** Instead of restricting mutation access for columns with column presets, ignore the value delivered by client for these columns. This way the clients can be more versatile.

**Playground:** https://warm-sierra-90192.herokuapp.com/console/api-explorer

Start with the linked column-presets documentation and reproduce the behavior in the Playground. Trace how a mutation handles a client-supplied value for a column with a role-specific preset. Done means the preset column's client value is ignored rather than rejected, while the preset behavior remains intact.

Written by the indexing model from the issue text.