Misleading "IGrainReferenceActivatorProvider not found" error when Grain interface uses named tuple parameters

**Title:**
Grain interface with named tuple parameters causes misleading activation error: "Unable to find an IGrainReferenceActivatorProvider for grain type session"

### Description

When defining a Grain interface method that uses **C# named tuples** as parameters (e.g., `(int x, long y)`), the Orleans runtime fails during grain activation with a misleading exception:

```
Unable to find an IGrainReferenceActivatorProvider for grain type session
```

This error occurs **even though the Grain itself is correctly registered**, and the actual root cause appears to be **serialization or code generation failure due to the use of named tuples in the method signature**.

### Reproduction Steps

1. Define a Grain interface like this:

```csharp
public interface ITestGrain : IGrainWithStringKey
{
Task TestFuncAsync((int x, long y) arg1, (int xx, long yy) arg2);
}
```

2. Implement the grain and register it in the silo.
3. Call `GrainFactory.GetGrain("key")` from client or another grain.
4. The call fails with the exception below.

### Exception Details

```
System.InvalidOperationException: Unable to find an IGrainReferenceActivatorProvider for grain type session
at Orleans.GrainReferences.GrainReferenceActivator.CreateActivator(GrainType grainType, GrainInterfaceType interfaceType)
at Orleans.GrainReferences.GrainReferenceActivator.CreateReference(GrainId grainId, GrainInterfaceType interfaceType)
at Orleans.GrainFactory.GetGrain(Type interfaceType, IdSpan grainKey, String grainClassNamePrefix)
at Orleans.GrainFactory.GetGrain[TGrainInterface](String primaryKey, String grainClassNamePrefix)
```

### Environment

- **Orleans Version**: 8.0.0
- **.NET Version**: .NET 8

Start with the GrainReferences.GrainReferenceActivator.CreateActivator and CreateReference entries shown in the stack trace, then reproduce the failure using the ITestGrain interface with named tuple parameters. Trace the related serialization or code-generation failure and verify the behavior against the reported Orleans 8.0.0 setup; done means named tuple parameters no longer produce the misleading activation error, or the underlying failure is reported clearly.

Written by the indexing model from the issue text.