Set context flag for when C++ language server is activated

The primary purpose of this is for this flag to be consumed by the C++ devtools extensions. This way the C++ specific Copilot tools will only appear in tools list and register when the C++ language server is actually activated.

Author: DavidARaygoza

Extension/src/LanguageServer/extension.ts

@@ -169,6 +169,7 @@ export async function activate(): Promise<void> {
         }
     }
 
+    await vscode.commands.executeCommand('setContext', 'cpptools.languageServerActivated', true);
     clients = new ClientCollection();
     ui = getUI();