Orleans.Runtime.OrleansConfigurationException: Found unserializable or uncopyable types which are being referenced in grain interface signatures

Problem:
I am encountering serialization issues with Orleans when using the `LanguageExt.Either` type in a grain interface (`IQuizGrain`).

Error Message:
Orleans.Runtime.OrleansConfigurationException: Found unserializable or uncopyable types which are being referenced in grain interface signatures:
Type: LanguageExt.Either`2[LanguageExt.Common.Error,LanguageExt.Unit] has no serializer or copier and was referenced by the following:
MasteryLadder.Quiz.Grains.IQuizGrain,MasteryLadder.Quiz.Grains methods: System.Threading.Tasks.Task`1[LanguageExt.Either`2[LanguageExt.Common.Error,LanguageExt.Unit]] Foo()
Ensure that all types which are used in grain interfaces have serializers available for them.
Applying the [GenerateSerializer] attribute to your type and adding [Id(x)] attributes to serializable properties and fields is the simplest way to accomplish this.Alternatively, for types which are outside of your control, serializers may have to be manually crafted, potentially using surrogate types.

Steps to Reproduce:
1. Define an Orleans grain interface (`IQuizGrain`) that includes a method returning `Task>`.
2. Attempt to run an Orleans application using this grain interface.

Expected Behavior:
The `LanguageExt.Either` type should be correctly serialized and deserialized by Orleans without configuration errors.

Actual Behavior:
Orleans throws a `OrleansConfigurationException` indicating that `LanguageExt.Either` lacks a serializer or copier.

Additional Information:
- Orleans version: 8.0

Start with the IQuizGrain interface and reproduce the Orleans 8.0 configuration check using Task>. Investigate serializer and copier support for the external LanguageExt.Either type; the issue is done when this grain signature no longer produces OrleansConfigurationException and the value can be serialized and deserialized.

Written by the indexing model from the issue text.