docs(telemetry): remove Phase reference from tempo.yaml additional-filter comment

Reviewer noted implementation-phase references should not appear in
shipped config comments. Drop the "Phase 3/4" token, keep the description.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

docker/telemetry/grafana/provisioning/datasources/tempo.yaml

@@ -180,7 +180,7 @@ datasources:
             operator: "="
             scope: span
             type: static
-          # Phase 3/4: Additional transaction and queue filters
+          # Additional transaction and queue filters
           - id: tx-path
             tag: path
             operator: "="