[ResponseOps][Task Manager] Task manager had an issue calculating capacity estimation. averageLoadPercentage: NaN (#216303)

Resolves https://github.com/elastic/kibana/issues/215045

## Summary

This PR removes this log as it's not needed and is causing alerts in
serverless.

x-pack/platform/plugins/shared/task_manager/server/monitoring/capacity_estimation.ts

@@ -279,7 +279,7 @@ export function withCapacityEstimate(
       };
     } catch (e) {
       // Return monitoredStats with out capacity estimation
-      logger.error(e.message);
+      logger.debug(e.message);
     }
   }
   return monitoredStats;