Add slack notifications to litmus nightly runs (#11648)
Add slack notifications to litmus nightly runs (#11648)

- Add a conditional slack notifications to litmus nightly job.
nooproblem/influxdb,mark-rushakoff/influxdb,influxdata/influxdb,li-ang/influxdb,influxdb/influxdb,mark-rushakoff/influxdb,influxdb/influxdb,nooproblem/influxdb,mark-rushakoff/influxdb,nooproblem/influxdb,nooproblem/influxdb,mark-rushakoff/influxdb,influxdb/influxdb,mark-rushakoff/influxdb,influxdata/influxdb,nooproblem/influxdb,influxdb/influxdb,li-ang/influxdb,influxdb/influxdb,influxdb/influxdb,mark-rushakoff/influxdb