.NET: [Bug]: CopySessionConfig() hardcodes Streaming = true, ignoring SessionConfig.Streaming value

[feiyun0112]

fix #4732

Note

since the default value of SessionConfig.Streaming is false, after this change, all instances creating a new SessionConfig must explicitly set Streaming = true. This will affect existing code that is already in use.

[Copilot]

Pull request overview

Fixes GitHub Copilot agent session config copying to respect the caller-provided SessionConfig.Streaming value (instead of hardcoding streaming on), aligning the .NET GitHub Copilot provider with SessionConfig semantics and unblocking scenarios where streaming must be disabled (issue #4732).

Changes:

• Update GitHubCopilotAgent.CopySessionConfig to copy Streaming from the source config.
• Update GitHubCopilotAgent.CopyResumeSessionConfig to preserve source.Streaming (defaulting to true only when source is null).
• Extend unit tests to cover Streaming=true in existing copy tests and add new tests asserting Streaming=false is preserved.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 3 comments.

File	Description
dotnet/src/Microsoft.Agents.AI.GitHub.Copilot/GitHubCopilotAgent.cs	Preserve Streaming when copying session configs; update XML docs accordingly.
dotnet/tests/Microsoft.Agents.AI.GitHub.Copilot.UnitTests/GitHubCopilotAgentTests.cs	Add/adjust unit tests to validate Streaming preservation behavior in copy helpers.