.NET Semantic Kernel - Add prompty file based functions from Kernel Builder

[christasmithgit]

Currently, there is no way to add prompty based prompt functions into the kernel when building. This makes uses them via DI or similar difficult and they need to be created on the fly

var function = kernel.CreateFunctionFromPromptyFile(promptyFilePath, fileProvider, promptTemplateFactory);

it would be good if we had a similar functionality to 'importpluginfrompromptdirectory'
https://learn.microsoft.com/en-us/dotnet/api/microsoft.semantickernel.kernelextensions.importpluginfrompromptdirectory?view=semantic-kernel-dotnet