Remove 10.14 suffix from osx nuget package

[jeffpardy]

Updates the specified runtime for osx to remove the OS specific RID. This is no longer supported since .NET 8 and generates the following warning as well as runtime errors.

Matches the same changes made in microsoft/onnxruntime with microsoft/onnxruntime#17277

Build Warning

/usr/local/share/dotnet/sdk/9.0.101/Sdks/Microsoft.NET.Sdk/targets/Microsoft.NET.Sdk.targets(322,5): warning NETSDK1206: Found version-specific or distribution-specific runtime identifier(s): osx.10.14-arm64, osx.10.14-x64. Affected libraries: Microsoft.ML.OnnxRuntime.Extensions. In .NET 8.0 and higher, assets for version-specific and distribution-specific runtime identifiers will not be found by default. See https://aka.ms/dotnet/rid-usage for details.

Runtime Error

Error Message
      : Microsoft.ML.OnnxRuntime.OnnxRuntimeException : [ErrorCode:NoSuchFile] The ONNX Runtime extensions library
       was not found. The Microsoft.ML.OnnxRuntime.Extensions NuGet package must be referenced by the project to u
      se 'OrtExtensions.RegisterCustomOps.
      Stack Trace:
         at Microsoft.ML.OnnxRuntime.SessionOptions.RegisterOrtExtensions()

[jeffpardy]

Thanks @wenbingl!
@skottmckay @edgchen1 anything else I can do?

[edgchen1]

@jeffpardy The changes look fine to me. I'm not very familiar with the NuGet setup though. Were you able to verify that this fixes the issues you encountered?

[ezhevita]

I can verify that it fixes runtime error and no longer requires custom ResolvingUnmanagedDll.

[skottmckay]

Should all these directories move to be 'net8.0-...' given net8 is the lowest version currently supported?

The xamarin targets (monoandroid11.0 and xamarinios10) can be deleted as well.

[jeffpardy]

Sorry @skottmckay I was away for a bit. Not opposed to that cleanup but would it be ok to do as a separate pull request? Just thinking it might increase the blast radius of this particular change?