Update activeDeadlineSeconds default value documentation

[simu]

Explicitly note that invalid annotation values to override the namespace limit will cause pod creation failures and give some tips on how to investigate.

Checklist

• Try to isolate changes into separate PRs (to build a better changelog).
• Categorize the PR by setting a good title and adding one of the labels:
  how-to, tutorial, reference, explanation, cicd, dependency
  as they show up in the changelog