During upgrade to FCV 9.0 timeseries collections will be converted automatically to viewless timeseries . The conversion will start after the cluster (including the config server) have already transitioned to FCV 9.0 and before the setFeatureComatibilityVersion command returns the response to the user. This means that if the conversion is interrupted by an error (e.g. network error, primary stepdown etc..) it will be the responsibility of the user or automation agent to keep retrying the setFeatureComatibilityVersion command until it will finally succeed. If the user won’t retry the operation interrupted during this phase, the cluster will remain in FCV 9.0 fully upgraded state but possibly with some legacy timeseries collections. (known setFCV limiration SERVER-106164).  

The goal of this ticket is to dectect and report those leftover legacy timeseries collections through CheckMetadataConsistency command.