Bump the time runit waits from kill to 20 secs

What does this Merge Request do and why?

This MR bumps the runit_wait_secs setting from 10 to 20 secs in an effort to reduce the flakiness of the verify:update_from_default_branch CI job.

Merge Request checklist

• This change is backward compatible. If not, please include steps to communicate to our users.
• Tests added for new functionality. If not, please raise Issue to follow-up.
• Documentation added/updated, if needed.
• gdk doctor test added, if needed.
• Add the ~highlight label if this MR should be included in the CHANGELOG.md.

Closes #1183 (closed)