feat: Check that schemas are well-formed upon construction

[OussamaSaoudi-db]

Please describe why this is necessary.

Delta disallows schemas that have two fields that differ only in case. For example, a schema with the fields id and ID is not allowed. This is also checked in the delta-spark implementation here.

Describe the functionality you are proposing.

Come up with a way to construct StructTypes that checks they are well-formed as defined by the reference implementation.

Additional context

For context on how this issue originally came up, look here.

Here's a non-exhaustive list of cases that should perform this check

• When a Schema is parsed from a string. This happens after parsing Metadata actions for instance.
• When a schema is passed to the kernel using the EngineSchemaVisitor in ffi/src/schema.rs.