remove unused agentMode param
remove unused agentMode param

Signed-off-by: Robbie Lankford <a694ed5d2af184717afe6b1b488fcc33ddbdcea1@grafana.com>

prometheus/prometheus,prometheus/prometheus,keegancsmith/prometheus,keegancsmith/prometheus,prometheus/prometheus,prometheus/prometheus,keegancsmith/prometheus,prometheus/prometheus,keegancsmith/prometheus,keegancsmith/prometheus