Avoid restarting monitor while app is exiting

[hluk]

This can happen if the app (the main server process) and the monitor process receive a request to exit from a session manager.

Fixes #3317

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 79.91%. Comparing base (82da74e) to head (8a39c79).
⚠️ Report is 1 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #3318      +/-   ##
==========================================
- Coverage   79.92%   79.91%   -0.01%     
==========================================
  Files         231      231              
  Lines       28442    28442              
==========================================
- Hits        22731    22730       -1     
- Misses       5711     5712       +1     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.