Add dotnet.automaticallySyncWithActiveItem to VS Code settings (#3992)

Enable automatic synchronization with the active item in VS Code for better
developer experience when working with .NET projects.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: SergeyMenshykh

dotnet/.vscode/settings.json

@@ -1,5 +1,6 @@
 {
     "dotnet.defaultSolution": "agent-framework-dotnet.slnx",
     "git.openRepositoryInParentFolders": "always",
-    "chat.agent.enabled": true
+    "chat.agent.enabled": true,
+    "dotnet.automaticallySyncWithActiveItem": true
 }