fix(cluster-agent): restore rate_limit_queries telemetry after external metrics refactor

QueryExternalMetric stopped calling updateRateLimitingMetrics() when parallel
query batching landed in #33272, so limit/remaining/period/reset gauges were no
longer published on the cluster-agent metrics endpoint.

Co-authored-by: Cursor <cursoragent@cursor.com>

Author: a7i

pkg/util/kubernetes/autoscalers/processor.go

@@ -222,6 +222,7 @@ func (p *Processor) QueryExternalMetric(queries []string, timeWindow time.Durati
 	_ = group.Wait()
 
 	log.Debugf("Processed %d chunks with %d chunks in global error", len(chunks), responsesGlobalErrors)
+	p.updateRateLimitingMetrics()
 	return responses
 }