health: remove exporting_metrics_lost template (#10829)

health/health.d/exporting.conf

@@ -21,14 +21,3 @@ families: *
    delay: down 5m multiplier 1.5 max 1h
     info: percentage of metrics sent to the external database server
       to: dba
-
-template: exporting_metrics_lost
-families: *
-      on: exporting_data_size
-   units: metrics
-    calc: abs($lost)
-   every: 10s
-    crit: ($this != 0) || ($status == $CRITICAL && abs($sent) == 0)
-   delay: down 5m multiplier 1.5 max 1h
-    info: number of metrics lost due to repeating failures to contact the external database server
-      to: dba