Fix Lab SCA1 scaffold details that no longer match the SPFx generator

[Elliot Margot (OwnOptic)]

Lab SCA1 tells you to scaffold with yo @microsoft/sharepoint@next. Three details in the lab describe output that tag no longer produces, checked against @microsoft/generator-sharepoint@1.24.0-beta.3.

React 17 -> React 18. The Exercise 2 note says the React template wires up React 17. The generator's copilotComponentReact dependency group pins react and react-dom at 18.3.1 and @types/react at 18.2.79.

The render() snippet in Exercise 3 is a React 17 mount. The scaffolded component imports createRoot from react-dom/client, keeps the root on the class so onTeardown() can unmount it, and passes onRequestDisplayMode and onRequestSizeChange down to the React component. The snippet showed ReactDOM.render(...) and neither callback, so it did not match the file the reader has just been told to open. Replaced with the scaffolded code, and the sentence above it now mentions the callbacks and the root.

IHelloWorldLabProps in Exercise 4 does not exist. The generator emits I<componentName>Props, so with the lab's component name it is IHelloWorldProps. The snippet as written does not compile.

Verified by running npm pack @microsoft/generator-sharepoint@next and reading lib/common/dependencies.json and lib/templates/copilotComponent/react/. Docs only, one file.