ValidationMessageStore.Add field accessor parameter shows a warning for nullable properties

Is there an existing issue for this?

• I have searched the existing issues

Describe the bug

Adding validation errors using the below ValidationMessageStore.Add method triggers a warning when nullable annotations are enabled for the project, and the property referenced in the accessor parameter has a nullable type.

https://github.com/dotnet/aspnetcore/blob/2f68ef8d42646046eb36ff2db5f17965a7893545/src/Components/Forms/src/ValidationMessageStore.cs#L38-L39

Expected Behavior

No warnings are displayed for properties with nullable type.

Steps To Reproduce

The following code shows how the warning message is triggered:

private TestModel model = new();

private class TestModel
{
    public string? Text { get; set; }
}

private void ManualValidation()
{
    var messageStore = new ValidationMessageStore(editContext);

    if (true /* External validation rule */)
    {
        messageStore?.Add(() => model.Text, "This value is not valid");
        //                      ^^^^^^^^^^  <-- Warning triggered here
    }
}

Full repro at https://github.com/vuorinem/aspnet_blazor_validationmessagestore_warning_repro/blob/6ba9b0a2b4fe0f38c1da6e7e5577dd75083dc9b6/BlazorApp1/Pages/Index.razor

Exceptions (if any)

No response

.NET Version

6.0.202

Anything else?

Changing the method signature to the following (from object to generic parameter TField) could fix the issue as far as I understand:

public void Add<TField>(Expression<Func<TField>> accessor, string message)

That would match the the method in FieldIdentifier:

https://github.com/dotnet/aspnetcore/blob/2f68ef8d42646046eb36ff2db5f17965a7893545/src/Components/Forms/src/FieldIdentifier.cs#L20