Conventional routing cannot identify the endpoint for action to query property without the key

[xuzhg]

Assemblies affected
Which assemblies and versions are known to be affected e.g. ASP.NET Core OData 8.x

Describe the bug
A clear and concise description of what the bug is.

Reproduce steps
The simplest set of steps to reproduce the issue. If possible, reference a commit that demonstrates the issue.

Data Model

public class CustomerService
{
    [Contained]
    public List<StoreCustomer> customers { get; set; } = new List<StoreCustomer>();
}

public class StoreCustomer
{
    public String id { get; set; }
}

Then we build the Edm model using a singleton as

modelBuilder.Singleton<CustomerService>("CustomerService");

The controller has the following:

    public class CustomerServiceController : ODataController
    {
        [EnableQuery]
        [HttpGet]
        public ActionResult<IEnumerable<StoreCustomer>> GetCustomers()
        {
            return Ok(CustomersController.customers);
        }
    }

Expected behavior
The conventional routing should identify 'GetCustomers' and build endpoints for it.

Actual behavior
There's no endpoint generated for this action.

Additional context
The root cause is that:

In the NavigationRoutingConvention, there's a logic as below:
https://github.com/OData/AspNetCoreOData/blob/main/src/Microsoft.AspNetCore.OData/Routing/Conventions/NavigationRoutingConvention.cs#L68-L74

bool hasKeyParameter = action.HasODataKeyParameter(entityType, context.Options?.RouteOptions?.EnablePropertyNameCaseInsensitive ?? false);
        if (!(context.Singleton != null ^ hasKeyParameter))
        {
            // Singleton, doesn't allow to query property with key
            // entityset, doesn't allow for non-key to query property
            return false;
        }

However, 'hasKeyParameter' should have 'false' but it has the 'true'.

HasODataKeyParameter has an issue to treat the entity type without key.