Configure response size limit for prometheus-relay

Related-To: PROD-36270
Change-Id: I45b90d54d1ac2c45af80cab120a263fc46621108
diff --git a/prometheus/files/relay/default b/prometheus/files/relay/default
index 80635d9..ff3c3b8 100644
--- a/prometheus/files/relay/default
+++ b/prometheus/files/relay/default
@@ -9,3 +9,6 @@
 {%- endif %}
 PROMETHEUS_RELAY_BIND_PORT={{ relay.bind.port }}
 PrometheusRelayClientTimeout={{ relay.client.timeout }}
+{%- if relay.get("response", {}).get("limit") %}
+PrometheusResponseLimitBytes={{ relay.response.limit }}
+{%- endif %}