Add warning message when tracker cannot ping machine-exec

[dkwon17]

What does this PR do?

This PR displays an error message to the user if the activity tracker extension fails to ping che-machine-exec. The activity tracker extension regularly pings che-machine-exec to prevent dev environment idling, therefore if the ping fails, this PR lets the user know that their workspace might idle.

What issues does this PR fix?

Fixes eclipse-che/che#23134

How to test this PR?

1. Create a workspace with the PR image as the editor URL
2. In the editor, run the following to terminate the che-machine-exec process:

// find machine-exec pid
ps -aux

kill -9 <pid>

3. Make any file edits in the editor.
4. Wait about 1 minute. After one minute, the error notification should appear:
   
5. Click on "View Logs" to view the error message in the extension's output:

Does this PR contain changes that override default upstream Code-OSS behavior?

• the PR contains changes in the code folder (you can skip it if your changes are placed in a che extension )
• the corresponding items were added to the CHANGELOG.md file
• rules for automatic git rebase were added to the .rebase folder

[github-actions]

Click here to review and test in web IDE:

[github-actions]

Pull Request images published ✨

Editor: quay.io/che-incubator-pull-requests/che-code:pr-443-amd64
Dev image: quay.io/che-incubator-pull-requests/che-code-dev:pr-443-dev-amd64

[github-actions]

Pull Request images published ✨

Editor: quay.io/che-incubator-pull-requests/che-code:pr-443-amd64
Dev image: quay.io/che-incubator-pull-requests/che-code-dev:pr-443-dev-amd64

[github-actions]

Pull Request images published ✨

Editor: quay.io/che-incubator-pull-requests/che-code:pr-443-amd64
Dev image: quay.io/che-incubator-pull-requests/che-code-dev:pr-443-dev-amd64

[github-actions]

Pull Request images published ✨

Editor: quay.io/che-incubator-pull-requests/che-code:pr-443-amd64
Dev image: quay.io/che-incubator-pull-requests/che-code-dev:pr-443-dev-amd64