.Net: Fix Amazon Bedrock UT (microsoft#11079)

### Motivation and Context

The given test was giving a false negative in environments where Bedrock
Runtime was property configured and could be retrieved from the DI
container.

This change ensures this test only executes when the environment has no
runtime configured to be recovered from the DI container.

Author: RogerBarreto

dotnet/src/Connectors/Connectors.Amazon.UnitTests/Services/BedrockTextEmbeddingGenerationServiceTests.cs

@@ -4,6 +4,8 @@
 using System.Collections.Generic;
 using System.Threading.Tasks;
 using Amazon.BedrockRuntime;
+using Amazon.Runtime;
+using Microsoft.Extensions.DependencyInjection;
 using Microsoft.SemanticKernel.Embeddings;
 using Microsoft.SemanticKernel.Services;
 using Moq;
@@ -72,19 +74,37 @@ public void ShouldThrowExceptionForEmptyModelId()
     /// Checks that an invalid BedrockRuntime object will throw an exception.
     /// </summary>
     [Fact]
-    public async Task ShouldThrowExceptionForNullBedrockRuntimeAsync()
+    public async Task ShouldThrowExceptionForNullBedrockRuntimeWhenNotConfiguredAsync()
     {
         // Arrange
         string modelId = "amazon.titan-embed-text-v2:0";
         List<string> prompts = new() { "King", "Queen", "Prince" };
         IAmazonBedrockRuntime? nullBedrockRuntime = null;
+        bool notConfigured = false;
 
-        // Act & Assert
-        await Assert.ThrowsAnyAsync<Exception>(async () =>
+        try
         {
-            var kernel = Kernel.CreateBuilder().AddBedrockTextEmbeddingGenerationService(modelId, nullBedrockRuntime).Build();
-            var service = kernel.GetRequiredService<ITextEmbeddingGenerationService>();
-            await service.GenerateEmbeddingsAsync(prompts).ConfigureAwait(true);
-        }).ConfigureAwait(true);
+            var runtime = new ServiceCollection()
+                .TryAddAWSService<IAmazonBedrockRuntime>()
+                .BuildServiceProvider()
+                .GetService<IAmazonBedrockRuntime>();
+        }
+        catch (AmazonClientException)
+        {
+            // If cannot grab the runtime from the container then we are not configured
+            notConfigured = true;
+        }
+
+        // Act
+        if (notConfigured)
+        {
+            // If No RegionEndpoint or ServiceURL is configured, the runtime will throw an exception
+            await Assert.ThrowsAnyAsync<Exception>(async () =>
+            {
+                var kernel = Kernel.CreateBuilder().AddBedrockTextEmbeddingGenerationService(modelId, nullBedrockRuntime).Build();
+                var service = kernel.GetRequiredService<ITextEmbeddingGenerationService>();
+                await service.GenerateEmbeddingsAsync(prompts).ConfigureAwait(true);
+            }).ConfigureAwait(true);
+        }
     }
 }