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

Author: kk7ds

.zuul.yaml

@@ -674,6 +674,8 @@
     description: Debian Bullseye platform test
     nodeset: devstack-single-node-debian-bullseye
     timeout: 9000
+    # TODO(danms) n-v until the known issue is resolved
+    voting: false
     vars:
       configure_swap_size: 4096