Fix missing resultType on complete result responses (#1684)

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Co-authored-by: Tarek Mahmoud Sayed <tarekms@ntdev.microsoft.com>

tests/ModelContextProtocol.Tests/Client/July2026ProtocolConnectionTests.cs

@@ -83,6 +83,7 @@ public class July2026ProtocolConnectionTests : ClientServerTestBase
 
         var discoverResult = JsonSerializer.Deserialize<DiscoverResult>(response.Result, McpJsonUtilities.DefaultOptions);
         Assert.NotNull(discoverResult);
+        Assert.Equal("complete", discoverResult.ResultType);
         Assert.Equal([McpProtocolVersions.July2026ProtocolVersion], discoverResult.SupportedVersions);
     }
 }