Simplify matching rules for nfs servers

alerts/nfs-down.rules

 ALERT GitNFSServerDown
-  IF min(up{fqdn=~"nfs-file[0-9]+.stor.gitlab.com"}) without (job) == 0
+  IF up{fqdn=~"nfs-file[0-9]+.stor.gitlab.com"} == 0
   FOR 2m
   LABELS {severity="critical", pager="pagerduty"}
   ANNOTATIONS {
@@ -9,7 +9,7 @@ ALERT GitNFSServerDown
   }
 ALERT FileNFSServerDown
-  IF min(up{fqdn=~"nfs-(uploads|share|lfs|artifacts)[0-9]+.stor.gitlab.com"}) without (job) == 0
+  IF up{fqdn=~"nfs-(uploads|share|lfs|artifacts)[0-9]+.stor.gitlab.com"} == 0
   FOR 2m
   LABELS {severity="critical", pager="pagerduty"}
   ANNOTATIONS {