.Net: Fix and put back Ollama tool asserts (#11046)

These were removed in a previous PR as OllamaSharp changed its API and
the previous code no longer compiled. This fixes the code and puts it
back.

Author: stephentoub

dotnet/src/Connectors/Connectors.Ollama.UnitTests/Services/OllamaChatCompletionTests.cs

@@ -305,6 +305,13 @@ public async Task GetChatMessageContentsShouldAdvertiseToolAsync()
         Assert.NotEmpty(requestPayload.Tools);
         Assert.Equal(1, requestPayload.Tools?.Count());
 
+        var firstTool = JsonSerializer.Deserialize<Tool>((requestPayload.Tools?.Cast<JsonElement>().First()!).Value);
+        Assert.Equal("TestPlugin_TestFunction", firstTool!.Function!.Name);
+        Assert.Single(firstTool.Function!.Parameters!.Properties!);
+        Assert.Equal("testInput", firstTool.Function!.Parameters!.Properties!.First().Key);
+        Assert.Equal("string", firstTool.Function!.Parameters!.Properties!.First().Value.Type);
+        Assert.Equal("testInput", firstTool.Function!.Parameters!.Required!.First());
+
         Assert.NotNull(message.ModelId);
         Assert.Equal(targetModel, message.ModelId);
         Assert.NotNull(message.InnerContent);
@@ -375,6 +382,13 @@ public async Task GetChatMessageContentsShouldAdvertiseAndTriggerToolAsync()
         Assert.NotEmpty(requestPayload.Tools);
         Assert.Equal(1, requestPayload.Tools?.Count());
 
+        var firstTool = JsonSerializer.Deserialize<Tool>((requestPayload.Tools?.Cast<JsonElement>().First()!).Value);
+        Assert.Equal("TestPlugin_TestFunction", firstTool!.Function!.Name);
+        Assert.Single(firstTool.Function!.Parameters!.Properties!);
+        Assert.Equal("testInput", firstTool.Function!.Parameters!.Properties!.First().Key);
+        Assert.Equal("string", firstTool.Function!.Parameters!.Properties!.First().Value.Type);
+        Assert.Equal("testInput", firstTool.Function!.Parameters!.Required!.First());
+
         Assert.Equal(1, invocationCount);
 
         Assert.NotNull(message.ModelId);