Local queries are case sensitive

Hi,

In working with local view of my data, I discovered an inconsistency. I wasn't able to find any documentation regarding this. Is this a bug or is it by design somehow?

```C#
dbContext.Platforms.SingleOrDefault(p => p.Id == "beleco").ShouldNotBeNull();
dbContext.Platforms.SingleOrDefault(p => p.Id == "Beleco").ShouldNotBeNull();
dbContext.Platforms.Load();
dbContext.Platforms.Local.SingleOrDefault(p => p.Id == "beleco").ShouldNotBeNull();
dbContext.Platforms.Local.SingleOrDefault(p => p.Id == "Beleco").ShouldNotBeNull(); // Fails!
```

EF Core version: 5.0.11
Database provider: Microsoft.EntityFrameworkCore.SqlServer
Target framework: .NET 5.0
Operating system: Windows
IDE: Jetbrains Rider 2021.2.1

Thanks!