The breakpoint isn't hit when remote debugging the Node.js web app

[v-meilei]

OS: All Build Version: v0.25.4-alpha

Repro Steps:

1. Run ''git clone https://github.com/Azure-Samples/nodejs-docs-hello-world" and then open this project in VS Code.
2. Create a linux node.js web app and deploy it.
3. Click "Yes" when popping up a notification to prompt you to update the workspace configuration to run build commands.
4. Browse the web app and check the website.
5. Right click this web app --> Select 'Start Remote Debugging'.
6. Select "Enable" when prompting to enable the remote debug.
7. Set a breakpoint at "Hello World" line in the index.js file.
8. Refresh the website and verify whether the breakpoint is hit.

Expect: The breakpoint is hit.

Actual: The breakpoint isn't hit.