docs(telemetry): remove Phase references from tempo.yaml RPC filter comments

Reviewer noted implementation-phase references should not appear in
shipped config comments. Drop the "Phase 2" tokens, keep descriptions.

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

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

@@ -6,7 +6,7 @@
 # Search filters provide pre-configured dropdowns in the Explore UI.
 # Each phase adds filters for the span attributes it introduces.
 # Phase 1b (infra): Base filters — node identity, service, span name, status.
-# Phase 2 (RPC):    RPC command, status, role filters.
+# RPC command, status, role filters.
 
 apiVersion: 1
 
@@ -90,7 +90,7 @@ datasources:
             operator: ">"
             scope: intrinsic
             type: dynamic
-          # Phase 2: RPC tracing filters
+          # RPC tracing filters
           - id: rpc-command
             tag: command
             operator: "="