[main only] Make watcher validation master job voting

#173
Remove memcached_sasl_enabled=True workaround.

Master job is now passing, let's make it voting for now.

Jira: https://issues.redhat.com/browse/OSPRH-17029

Signed-off-by: Chandan Kumar (raukadah) <[email protected]>

Author: raukadah

.zuul.yaml

@@ -229,10 +229,6 @@
 - job:
     name: watcher-operator-validation-master
     parent: watcher-operator-validation-base
-    # Note(Chandankumar): Make it voting once
-    # github.com/openstack-k8s-operators/watcher-operator/pull/168#issuecomment-2897402858
-    # resolves.
-    voting: false
     description: |
       A Zuul job consuming content from openstack-meta-content-provider-master
       and deploying EDPM with master content. It configures an NFS server in a