Bump and clean up Nuget packages after .NET 10 upgrade

[rmunn]

Some packages (such as System.Linq.AsyncEnumerable) are no longer needed as they are included in the .NET 10 core libraries. But there are some method renames, such as .SelectAwait -> .Select, so there will be a few more changes than merely removing the package reference.

We will also consider moving from EF Core 9 to EF Core 10, though if that proves complicated then we'll bump that to a separate PR.

[rmunn]

https://learn.microsoft.com/en-us/ef/core/what-is-new/ef-core-10.0/breaking-changes lists mostly things that I expect not to affect us, but one might: "ExecuteUpdateAsync now accepts a regular, non-expression lambda" (instead of an expression tree). I checked our uses of ExecuteUpdate and it looks like all of them are already regular lambdas, so I don't think the update to EF Core 10 will break any of our code.

[rmunn]

We will also need to update Harmony to have a .NET 10 build, otherwise we can't upgrade Harmony's dependency on Microsoft.EntityFrameworkCore to 10.0.7, which in turn causes version conflicts.

[rmunn]

We will also need to update Harmony to have a .NET 10 build, otherwise we can't upgrade Harmony's dependency on Microsoft.EntityFrameworkCore to 10.0.7, which in turn causes version conflicts.

sillsdev/harmony#62