AthenaMonitoring: Fix histogram ownership.
When we create a TEfficiency, make sure it's owned by the root ROOT directory. Otherwise, it can be owned by an open data file and thus deleted prematurely. See !24350 (merged).
When we create a TEfficiency, make sure it's owned by the root ROOT directory. Otherwise, it can be owned by an open data file and thus deleted prematurely. See !24350 (merged).