Drop the traces dashboard, keep the datasource wiring

The dashboard reimplemented, less well, what Explore already does: its search
panel had no TraceQL query builder and no autocompletion, and its service
dependency table replaced an interactive node graph with a list. Searching and
exploring traces belongs in Explore.

The datasource correlations this work also fixed are kept — they are what was
actually missing, and they apply in Explore exactly as they would in a
dashboard.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

k8s/grafana/dashboards/kustomization.yaml

@@ -25,7 +25,6 @@ configMapGenerator:
       - obs-kong-gateways.json
       - obs-librechat.json
       - obs-stack-health.json
-      - obs-traces.json
       # <<< dashboards <<<
 
 generatorOptions: