.Net: OrderedAIServiceSelector logic should change as specified in is…

…sue 4234 (#4265)

### Motivation and Context

Closes #4234 

### Description

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

### 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)
and the [pre-submission formatting
script](https://github.com/microsoft/semantic-kernel/blob/main/CONTRIBUTING.md#development-scripts)
raises no violations
- [ ] All unit tests pass, and I have added new tests where possible
- [ ] I didn't break anyone 😄

dotnet/src/SemanticKernel.Abstractions/Services/OrderedAIServiceSelector.cs

@@ -35,6 +35,7 @@ public bool TrySelectAIService<T>(
         else
         {
             PromptExecutionSettings? defaultExecutionSettings = null;
+            // Search by service id first
             foreach (var keyValue in executionSettings)
             {
                 var settings = keyValue.Value;
@@ -52,6 +53,13 @@ public bool TrySelectAIService<T>(
                         return true;
                     }
                 }
+            }
+
+            // Search by model id next
+            foreach (var keyValue in executionSettings)
+            {
+                var settings = keyValue.Value;
+                var serviceId = keyValue.Key;
                 if (!string.IsNullOrEmpty(settings.ModelId))
                 {
                     service = this.GetServiceByModelId<T>(kernel, settings.ModelId!);
@@ -63,6 +71,7 @@ public bool TrySelectAIService<T>(
                 }
             }
 
+            // Search for default service id last
             if (defaultExecutionSettings is not null)
             {
                 service = GetAnyService(kernel);