.Net: reintroduce publish config and set IsPackable to false for Func…

…tions.OpenApi.Extensions project (#4954)

### Motivation and Context

Follow-up PR from #4867
Initially we removed publish config to prevent NuGet publishing. But
opening of the solution readds the publish config.

### Description

- Introduces publish config
- Prevents package publishing with `IsPackable` property in `.csproj`.

### Contribution Checklist

<!-- Before submitting this PR, please make sure: -->

- [x] The code builds clean without any errors or warnings
- [x] The PR follows the [SK Contribution
Guidelines](https://github.com/microsoft/semantic-kernel/blob/main/CONTRIBUTING.md)
and the [pre-submission formatting
script](https://github.com/microsoft/semantic-kernel/blob/main/CONTRIBUTING.md#development-scripts)
raises no violations
- [x] All unit tests pass, and I have added new tests where possible
- [x] I didn't break anyone 😄

dotnet/SK-dotnet.sln

@@ -206,7 +206,7 @@ Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "DocumentationExamples", "sa
 EndProject
 Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "CreateChatGptPlugin", "samples\CreateChatGptPlugin\Solution\CreateChatGptPlugin.csproj", "{87AB5AF5-5783-4372-9789-664895E0A2FF}"
 EndProject
-Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Functions.OpenApi.Extensions", "src\Functions\Functions.OpenApi.Extensions\Functions.OpenApi.Extensions.csproj", "{95CAA25F-A0DE-4A5B-92BA-7D56C0E822A8}"
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Functions.OpenApi.Extensions", "src\Functions\Functions.OpenApi.Extensions\Functions.OpenApi.Extensions.csproj", "{95CAA25F-A0DE-4A5B-92BA-7D56C0E822A8}"
 EndProject
 Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "Text", "Text", "{EB2C141A-AE5F-4080-8790-13EB16323CEF}"
 	ProjectSection(SolutionItems) = preProject
@@ -496,6 +496,8 @@ Global
 		{87AB5AF5-5783-4372-9789-664895E0A2FF}.Release|Any CPU.Build.0 = Release|Any CPU
 		{95CAA25F-A0DE-4A5B-92BA-7D56C0E822A8}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
 		{95CAA25F-A0DE-4A5B-92BA-7D56C0E822A8}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{95CAA25F-A0DE-4A5B-92BA-7D56C0E822A8}.Publish|Any CPU.ActiveCfg = Publish|Any CPU
+		{95CAA25F-A0DE-4A5B-92BA-7D56C0E822A8}.Publish|Any CPU.Build.0 = Publish|Any CPU
 		{95CAA25F-A0DE-4A5B-92BA-7D56C0E822A8}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{95CAA25F-A0DE-4A5B-92BA-7D56C0E822A8}.Release|Any CPU.Build.0 = Release|Any CPU
 	EndGlobalSection

dotnet/src/Functions/Functions.OpenApi.Extensions/Functions.OpenApi.Extensions.csproj

@@ -12,6 +12,7 @@
     <!-- NuGet Package Settings -->
     <Title>Semantic Kernel - OpenAPI Plugin Extensions</Title>
     <Description>Semantic Kernel OpenAPI Plugin Extensions</Description>
+    <IsPackable>false</IsPackable>
   </PropertyGroup>
   <ItemGroup>
     <ProjectReference Include="..\..\SemanticKernel.Core\SemanticKernel.Core.csproj" />