Make debian-bullseye job non-voting

As noted in the QA meeting this week, this job is failing due to
something that seems outside of our control:

https://meetings.opendev.org/meetings/qa/2022/qa.2022-11-08-15.00.log.html

Make it non-voting until that is resolved.

Change-Id: Ia571d1dab45eb1bbb8665373d416515d3c95fb14
1 file changed