unable to rebuild the SharePointSSOAppCustomizer SPFx extension from scratch

从 SSOSamples/SharePointSSOAppCustomizer 开始，检查 lib/components/SharePointSSOAppCustomizer/AgentChat/AgentChat.js，以及报告的包导出问题和 @microsoft/agents-copilotstudio-client 依赖项错误。运行示例的 rebuild 和 serve 步骤；当 SPFx 扩展能够在没有这些模块解析错误的情况下完成构建并提供服务时，即表示完成。

What sample tool are you using?
SharePointSSOAppCustomizer
https://github.com/microsoft/CopilotStudioSamples/tree/main/SSOSamples/SharePointSSOAppCustomizer

Describe the bug
I tried to rebuild the sample but got issues when serving the app

] Error - [webpack] 'dist':
./lib/components/SharePointSSOAppCustomizer/AgentChat/AgentChat.js:65:42-86: Module not found: Error: Package path . is not exported from package C:\SharePointSSOAppCustomizer\node_modules\botframework-webchat-fluent-theme (see exports field in C:\SharePointSSOAppCustomizer\node_modules\botframework-webchat-fluent-theme\package.json)        
./node_modules/@microsoft/agents-copilotstudio-client/dist/src/copilotStudioClient.js:17:29-42: Module not found: Error: Can't resolve 'os' in 'C:\SharePointSSOAppCustomizer\node_modules\@microsoft\agents-copilotstudio-client\dist\src'
BREAKING CHANGE: webpack < 5 used to include polyfills for node.js core modules by default.
This is no longer the case. Verify if you need this module and configure a polyfill for it.
If you want to include a polyfill, you need to:
        - add a fallback 'resolve.fallback: { "os": require.resolve("os-browserify/browser") }'
        - install 'os-browserify'
If you don't want to include a polyfill, you can use an empty module like this:
        resolve.fallback: { "os": false }

To Reproduce
Steps to reproduce the behavior:
Rebuilding the app and running the extension through the previous error

Expected behavior
I rebuilt the SPFx extension as expected and was able to get it working.

Additional context
Add any other context about the problem here.