.NET Agents - Fix enum handling of function parameters (#10513)

### Motivation and Context

`OpenAIAssistant` and `AzureAIAgent` fail when describing a function
with an enum parameter.

### Description
<!-- Describe your changes, the overall approach, the underlying design.
These notes will help understanding how your code works. Thanks! -->

Remove custom logic and reconcile processing with
`JsonSchemaFunctionParameters` and `KernelJsonSchema` that is now
available.

### 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/samples/Concepts/Concepts.csproj

@@ -147,9 +147,6 @@
     <EmbeddedResource Include="Resources\*">
       <CopyToOutputDirectory>Always</CopyToOutputDirectory>
     </EmbeddedResource>
-    <EmbeddedResource Include="Resources\Agents\*">
-      <CopyToOutputDirectory>Always</CopyToOutputDirectory>
-    </EmbeddedResource>
   </ItemGroup>
   <ItemGroup>
     <None Remove="Resources\Plugins\EventPlugin\openapiV1.json" />

dotnet/samples/GettingStartedWithAgents/AzureAIAgent/Step01_AzureAIAgent.cs

@@ -1,78 +1,20 @@
 // Copyright (c) Microsoft. All rights reserved.
-using System.ComponentModel;
 using Azure.AI.Projects;
 using Microsoft.SemanticKernel;
-using Microsoft.SemanticKernel.Agents;
 using Microsoft.SemanticKernel.Agents.AzureAI;
-using Microsoft.SemanticKernel.ChatCompletion;
 using Resources;
 using Agent = Azure.AI.Projects.Agent;
 
 namespace GettingStarted.AzureAgents;
 
 /// <summary>
 /// This example demonstrates similarity between using <see cref="AzureAIAgent"/>
-/// and <see cref="ChatCompletionAgent"/> (see: Step 2).
+/// and other agent types.
 /// </summary>
 public class Step01_AzureAIAgent(ITestOutputHelper output) : BaseAgentsTest(output)
 {
-    private const string HostName = "Host";
-    private const string HostInstructions = "Answer questions about the menu.";
-
     [Fact]
-    public async Task UseSingleAssistantAgentAsync()
-    {
-        // Define the agent
-        AzureAIClientProvider clientProvider = this.GetAzureProvider();
-        AgentsClient client = clientProvider.Client.GetAgentsClient();
-
-        Agent definition = await client.CreateAgentAsync(
-            TestConfiguration.AzureAI.ChatModelId,
-            HostName,
-            null,
-            HostInstructions);
-        AzureAIAgent agent = new(definition, clientProvider)
-        {
-            Kernel = new Kernel(),
-        };
-
-        // Initialize plugin and add to the agent's Kernel (same as direct Kernel usage).
-        KernelPlugin plugin = KernelPluginFactory.CreateFromType<MenuPlugin>();
-        agent.Kernel.Plugins.Add(plugin);
-
-        // Create a thread for the agent conversation.
-        AgentThread thread = await client.CreateThreadAsync(metadata: AssistantSampleMetadata);
-
-        // Respond to user input
-        try
-        {
-            await InvokeAgentAsync("Hello");
-            await InvokeAgentAsync("What is the special soup and its price?");
-            await InvokeAgentAsync("What is the special drink and its price?");
-            await InvokeAgentAsync("Thank you");
-        }
-        finally
-        {
-            await client.DeleteThreadAsync(thread.Id);
-            await client.DeleteAgentAsync(agent.Id);
-        }
-
-        // Local function to invoke agent and display the conversation messages.
-        async Task InvokeAgentAsync(string input)
-        {
-            ChatMessageContent message = new(AuthorRole.User, input);
-            await agent.AddChatMessageAsync(thread.Id, message);
-            this.WriteAgentChatMessage(message);
-
-            await foreach (ChatMessageContent response in agent.InvokeAsync(thread.Id))
-            {
-                this.WriteAgentChatMessage(response);
-            }
-        }
-    }
-
-    [Fact]
-    public async Task UseTemplateForAssistantAgentAsync()
+    public async Task UseTemplateForAzureAgentAsync()
     {
         // Define the agent
         string generateStoryYaml = EmbeddedResource.Read("GenerateStory.yaml");
@@ -102,11 +44,11 @@ public async Task UseTemplateForAssistantAgentAsync()
 
             // Invoke the agent with the override arguments.
             await InvokeAgentAsync(
-                        new()
-                        {
-                            { "topic", "Cat" },
-                            { "length", "3" },
-                        });
+                new()
+                {
+                    { "topic", "Cat" },
+                    { "length", "3" },
+                });
         }
         finally
         {
@@ -123,22 +65,4 @@ async Task InvokeAgentAsync(KernelArguments? arguments = null)
             }
         }
     }
-
-    private sealed class MenuPlugin
-    {
-        [KernelFunction, Description("Provides a list of specials from the menu.")]
-        [System.Diagnostics.CodeAnalysis.SuppressMessage("Design", "CA1024:Use properties where appropriate", Justification = "Too smart")]
-        public string GetSpecials() =>
-            """
-            Special Soup: Clam Chowder
-            Special Salad: Cobb Salad
-            Special Drink: Chai Tea
-            """;
-
-        [KernelFunction, Description("Provides the price of the requested menu item.")]
-        public string GetItemPrice(
-            [Description("The name of the menu item.")]
-            string menuItem) =>
-            "$9.99";
-    }
 }