Fix idle shutdown from happening when active process is still running

[NewtonDer]

Issue

Description of Changes

Testing

Screenshots/Videos

Additional Notes

Backporting

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[vpaiu]

The build fails without this line (The exact build error: Error: /home/ubuntu/environment/code-editor/code-editor-src/src/vs/server/node/webClientServer.ts(602,25): Cannot find name 'spawn'.).

I added back this line when testing for the build to be successful.

[NewtonDer]

thank you!

[vpaiu]

After I fixed locally the build error I did the following to test the idle-extension:

1. Created the sagemaker image with the build artifact.
2. Created the sagemaker code editor space in SageMaker Unified Studio with the image created.
3. Tested that the timestamp is updated properly by executing cat /tmp/.sagemaker-last-active-timestamp in the terminal in the code editor space. It printed the expected timestamp.
4. Tested that the api edpoint (/api/idle/) was returning the correct timestamp. I did this by executing fetch(window.location.pathname + '/api/idle').then(r => r.json()).then(console.log) in the web developer tools console. It returned the correct timestamp.