Cosmos: Unable to use value conversion for primitive collection

### Bug description

__Issue:__
When trying to convert from a `Dictionary<(Guid, Guid), string>` into a flattened `List<(string, string, string)>` I get the following error:
```
The 'List>' property 'Root.Matrix' could not be mapped because the database provider does not support this type. Consider converting the property value to a type supported by the database using a value converter.
```
I thought the issue was that I am using a primitive collection and EF would expect and actual reference object so I did try to replace the `Tuple` with an actual class with 3 string properties, i.e.:
```
public class MatrixEntry(string X, string Y, string Value);
```
But this did not solve the error either.

### Your code

```csharp
using Microsoft.EntityFrameworkCore;
using Microsoft.EntityFrameworkCore.Metadata.Builders;

var endpointUri = "https://localhost:8081";
var primaryKey = "";
var database = "testDb";

var options = new DbContextOptionsBuilder().UseCosmos(endpointUri, primaryKey, database).Options;
var dbContext = new AppDbContext(options);

var root = new Root();
root.Matrix.Add(Guid.CreateVersion7(), Guid.CreateVersion7(), "100");

dbContext.Roots.Add(root);
dbContext.SaveChanges();

public class Root
{
public Guid Id { get; set; } = Guid.CreateVersion7();
public string PartitionKey = "Root";
public GuidMatrix Matrix { get; set; } = [];

}

public class GuidMatrix : Dictionary<(Guid, Guid), string>
{
public void Add(Guid x, Guid y, string value)
{
this[(x, y)] = value;
this[(y, x)] = value;
}
}

public class AppDbContext(DbContextOptions options) : DbContext(options)
{
public DbSet Roots { get; set; }

protected override void OnModelCreating(ModelBuilder modelBuilder)
{
modelBuilder.HasDefaultContainer("public");
modelBuilder.ApplyConfigurationsFromAssembly(typeof(AppDbContext).Assembly);
base.OnModelCreating(modelBuilder);
}}

public class RootConfiguration : IEntityTypeConfiguration
{
public void Configure(EntityTypeBuilder builder)
{
builder.HasKey(x => x.Id);
builder.HasPartitionKey(x => x.PartitionKey);
builder.Property(x => x.Matrix)
.HasConversion(x => FlattenMatrix(x), y => ReconstructMatrix(y));
}

private static List<(string, string, string)> FlattenMatrix(GuidMatrix matrix)
{
var result = new List<(string, string, string)>();
var processedPairs = new List<(Guid, Guid)>();

foreach (var kv in matrix)
{
var x = kv.Key.Item1;
var y = kv.Key.Item2;

if (processedPairs.Contains((x, y)) || processedPairs.Contains((y, x))) continue;

result.Add((x.ToString(), y.ToString(), kv.Value));
processedPairs.Add((x, y));
}

return result;
}

private static GuidMatrix ReconstructMatrix(List<(string, string, string)> list)
{
var matrix = new GuidMatrix();

foreach (var (x, y, value) in list)
{
matrix.Add((Guid.Parse(x), Guid.Parse(y)), value);
}

return matrix;
}
}
```

### Stack traces

```text
"C:\Program Files\JetBrains\JetBrains Rider 2021.3.2\plugins\dpa\DotFiles\JetBrains.DPA.Runner.exe" --handle=18444 --backend-pid=10652 --etw-collect-flags=67108622 --detach-event-name=dpa.detach.10652.23 --refresh-interval=1 -- C:/Users/ny46864/dev/SampeApp/bin/Debug/net9.0/SampeApp.exe
Unhandled exception. System.InvalidOperationException: The 'List>' property 'Root.Matrix' could not be mapped because the database provider does not support this type. Consider converting the property value to a type supported by the database using a value converter. See https://aka.ms/efcore-docs-value-converters for more information. Alternately, exclude the property from the model using the '[NotMapped]' attribute or by using 'EntityTypeBuilder.Ignore' in 'OnModelCreating'.
at Microsoft.EntityFrameworkCore.Infrastructure.ModelValidator.ThrowPropertyNotMappedException(String propertyType, IConventionTypeBase typeBase, IConventionProperty unmappedProperty)
at Microsoft.EntityFrameworkCore.Infrastructure.ModelValidator.g__Validate|7_0(IConventionTypeBase typeBase, <>c__DisplayClass7_0&)
at Microsoft.EntityFrameworkCore.Infrastructure.ModelValidator.ValidatePropertyMapping(IModel model, IDiagnosticsLogger`1 logger)
at Microsoft.EntityFrameworkCore.Cosmos.Infrastructure.Internal.CosmosModelValidator.ValidatePropertyMapping(IModel model, IDiagnosticsLogger`1 logger)
at Microsoft.EntityFrameworkCore.Infrastructure.ModelValidator.Validate(IModel model, IDiagnosticsLogger`1 logger)
at Microsoft.EntityFrameworkCore.Cosmos.Infrastructure.Internal.CosmosModelValidator.Validate(IModel model, IDiagnosticsLogger`1 logger)
at Microsoft.EntityFrameworkCore.Infrastructure.ModelRuntimeInitializer.Initialize(IModel model, Boolean designTime, IDiagnosticsLogger`1 validationLogger)
at Microsoft.EntityFrameworkCore.Infrastructure.ModelSource.GetModel(DbContext context, ModelCreationDependencies modelCreationDependencies, Boolean designTime)
at Microsoft.EntityFrameworkCore.Internal.DbContextServices.CreateModel(Boolean designTime)
at Microsoft.EntityFrameworkCore.Internal.DbContextServices.get_Model()
at Microsoft.EntityFrameworkCore.Infrastructure.EntityFrameworkServicesBuilder.<>c.b__8_4(IServiceProvider p)
at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitFactory(FactoryCallSite factoryCallSite, RuntimeResolverContext context)
at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor`2.VisitCallSiteMain(ServiceCallSite callSite, TArgument argument)
at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitCache(ServiceCallSite callSite, RuntimeResolverContext context, ServiceProviderEngineScope serviceProviderEngine, RuntimeResolverLock lockType)
at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitScopeCache(ServiceCallSite callSite, RuntimeResolverContext context)
at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor`2.VisitCallSite(ServiceCallSite callSite, TArgument argument)
at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitConstructor(ConstructorCallSite constructorCallSite, RuntimeResolverContext context)
at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor`2.VisitCallSiteMain(ServiceCallSite callSite, TArgument argument)
at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitCache(ServiceCallSite callSite, RuntimeResolverContext context, ServiceProviderEngineScope serviceProviderEngine, RuntimeResolverLock lockType)
at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitScopeCache(ServiceCallSite callSite, RuntimeResolverContext context)
at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor`2.VisitCallSite(ServiceCallSite callSite, TArgument argument)
at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitConstructor(ConstructorCallSite constructorCallSite, RuntimeResolverContext context)
at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor`2.VisitCallSiteMain(ServiceCallSite callSite, TArgument argument)
at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitCache(ServiceCallSite callSite, RuntimeResolverContext context, ServiceProviderEngineScope serviceProviderEngine, RuntimeResolverLock lockType)
at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitScopeCache(ServiceCallSite callSite, RuntimeResolverContext context)
at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor`2.VisitCallSite(ServiceCallSite callSite, TArgument argument)
at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitConstructor(ConstructorCallSite constructorCallSite, RuntimeResolverContext context)
at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor`2.VisitCallSiteMain(ServiceCallSite callSite, TArgument argument)
at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitCache(ServiceCallSite callSite, RuntimeResolverContext context, ServiceProviderEngineScope serviceProviderEngine, RuntimeResolverLock lockType)
at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitScopeCache(ServiceCallSite callSite, RuntimeResolverContext context)
at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor`2.VisitCallSite(ServiceCallSite callSite, TArgument argument)
at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitConstructor(ConstructorCallSite constructorCallSite, RuntimeResolverContext context)
at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor`2.VisitCallSiteMain(ServiceCallSite callSite, TArgument argument)
at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitCache(ServiceCallSite callSite, RuntimeResolverContext context, ServiceProviderEngineScope serviceProviderEngine, RuntimeResolverLock lockType)
at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitScopeCache(ServiceCallSite callSite, RuntimeResolverContext context)
at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor`2.VisitCallSite(ServiceCallSite callSite, TArgument argument)
at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitConstructor(ConstructorCallSite constructorCallSite, RuntimeResolverContext context)
at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor`2.VisitCallSiteMain(ServiceCallSite callSite, TArgument argument)
at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitCache(ServiceCallSite callSite, RuntimeResolverContext context, ServiceProviderEngineScope serviceProviderEngine, RuntimeResolverLock lockType)
at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitScopeCache(ServiceCallSite callSite, RuntimeResolverContext context)
at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor`2.VisitCallSite(ServiceCallSite callSite, TArgument argument)
at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.Resolve(ServiceCallSite callSite, ServiceProviderEngineScope scope)
at Microsoft.Extensions.DependencyInjection.ServiceLookup.DynamicServiceProviderEngine.<>c__DisplayClass2_0.b__0(ServiceProviderEngineScope scope)
at Microsoft.Extensions.DependencyInjection.ServiceProvider.GetService(ServiceIdentifier serviceIdentifier, ServiceProviderEngineScope serviceProviderEngineScope)
at Microsoft.Extensions.DependencyInjection.ServiceLookup.ServiceProviderEngineScope.GetService(Type serviceType)
at Microsoft.Extensions.DependencyInjection.ServiceProviderServiceExtensions.GetRequiredService(IServiceProvider provider, Type serviceType)
at Microsoft.Extensions.DependencyInjection.ServiceProviderServiceExtensions.GetRequiredService[T](IServiceProvider provider)
at Microsoft.EntityFrameworkCore.DbContext.get_DbContextDependencies()
at Microsoft.EntityFrameworkCore.DbContext.get_ContextServices()
at Microsoft.EntityFrameworkCore.DbContext.get_InternalServiceProvider()
at Microsoft.EntityFrameworkCore.DbContext.Microsoft.EntityFrameworkCore.Infrastructure.IInfrastructure.get_Instance()
at Microsoft.EntityFrameworkCore.Infrastructure.Internal.InfrastructureExtensions.GetService(IInfrastructure`1 accessor, Type serviceType)
at Microsoft.EntityFrameworkCore.Infrastructure.Internal.InfrastructureExtensions.GetService[TService](IInfrastructure`1 accessor)
at Microsoft.EntityFrameworkCore.Infrastructure.AccessorExtensions.GetService[TService](IInfrastructure`1 accessor)
at Microsoft.EntityFrameworkCore.Infrastructure.DatabaseFacade.get_Dependencies()
at Microsoft.EntityFrameworkCore.Infrastructure.DatabaseFacade.EnsureDeletedAsync(CancellationToken cancellationToken)
at Program.$(String[] args) in C:\Users\ny46864\dev\SampeApp\Program.cs:line 14
at Program.(String[] args)
```

### Verbose output

```text

```

### EF Core version

9.0.0

### Database provider

Microsoft.EntityFrameworkCore.Cosmos

### Target framework

.NET 9.0

### Operating system

Windows 10

### IDE

_No response_

Start with the minimal Cosmos repro in the issue and the RootConfiguration.OnModelCreating path, then trace Cosmos model validation for the converted Matrix property. Verify whether the model can be built and saved with the shown Dictionary to List<(string, string, string)> conversion; done means the property is mapped without the reported unsupported-type exception.

Written by the indexing model from the issue text.