Double-counting when using labels for subgroups

Problem/Motivation

Collectors emit both an unlabeled total AND per-label metrics, causing sum() queries in Prometheus to return incorrect results.

Affected collectors:

• NodeCount / RevisionCount
• UserCount
• CommentCollector

For example:

# HELP drupal_revision_count_total Total revision count.
# TYPE drupal_revision_count_total gauge
drupal_revision_count_total 1
drupal_revision_count_total{bundle="article"} 1
drupal_revision_count_total{bundle="page"} 0

When I do a sum(drupal_revision_count_total) I'll get the count of 1 with no labels, but also the count for the bundle="article".

Proposed resolution

Only emit labeled metrics when labels are configured. This follows Prometheus best practices.

• NodeCount/RevisionCount: emit per-bundle metrics only when bundles configured, otherwise emit unlabeled total
• UserCount: emit only activated/blocked labeled metrics
• CommentCollector: emit only published/not published labeled metrics

Remaining tasks

User interface changes

API changes

Data model changes