.Net: Exposing ToJson method on FoundryProcessBuilder. (#12200)

Exposing the `ToJsonAsync` method on the `FoundryProcessBuilder` to that
users can save the JSON if needed.

### Contribution Checklist

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

Co-authored-by: Mark Wallace <127216156+markwallace-microsoft@users.noreply.github.com>

Author: alliscode

dotnet/samples/GettingStartedWithProcesses/Step06/Step06_FoundryAgentProcess.cs

@@ -98,10 +98,12 @@ public async Task ProcessWithTwoAgentMathChat()
         processBuilder.OnEvent(teacher, "correct_answer")
             .StopProcess();
 
-        /**************************** Build and Deploy ***************************/
+        // Verify that the process can be built and serialized to json
+        var processJson = await processBuilder.ToJsonAsync();
+        Assert.NotEmpty(processJson);
 
-        var process = processBuilder.Build();
-        var foundryWorkflowId = await processBuilder.DeployToFoundryAsync(process, TestConfiguration.AzureAI.WorkflowEndpoint);
+        var foundryWorkflowId = await processBuilder.DeployToFoundryAsync(TestConfiguration.AzureAI.WorkflowEndpoint);
+        Assert.NotEmpty(foundryWorkflowId);
     }
 
     /// <summary>

dotnet/src/Experimental/Process.Core/FoundryProcessBuilder.cs

@@ -157,13 +157,16 @@ public KernelProcess Build(KernelProcessStateMetadata? stateMetadata = null)
     /// <summary>
     /// Deploys the process to Azure Foundry.
     /// </summary>
-    /// <param name="process">The built process to deploy.</param>
     /// <param name="endpoint">Th workflow endpoint to deploy to.</param>
     /// <param name="credential">The credential to use.</param>
     /// <param name="cancellationToken"></param>
     /// <returns></returns>
-    public async Task<string> DeployToFoundryAsync(KernelProcess process, string endpoint, TokenCredential? credential = null, CancellationToken cancellationToken = default)
+    public async Task<string> DeployToFoundryAsync(string endpoint, TokenCredential? credential = null, CancellationToken cancellationToken = default)
     {
+        // Build the process
+        var process = this.Build();
+
+        // Serialize and deploy
         using var httpClient = new HttpClient();
         if (credential != null)
         {
@@ -192,6 +195,16 @@ public async Task<string> DeployToFoundryAsync(KernelProcess process, string end
         return foundryWorkflow?.Id ?? throw new KernelException("Failed to parse the response from Foundry.");
     }
 
+    /// <summary>
+    /// Serializes the process to JSON.
+    /// </summary>
+    public async Task<string> ToJsonAsync()
+    {
+        var process = this.Build();
+        var workflow = await WorkflowBuilder.BuildWorkflow(process).ConfigureAwait(false);
+        return WorkflowSerializer.SerializeToJson(workflow);
+    }
+
     private class FoundryWorkflow
     {
         [JsonPropertyName("id")]