Make range deleter service observer register tasks with ongoing queries future

The range deleter service observer is currently registering tasks (here and here) by relying on the default value of waitForActiveQueriesToComplete.

Purpose of this ticket is to register the tasks by passing the proper future that gets marked as ready once ongoing queries retaining the range are finishing.

As part of this ticket, remember to featureflag the "wait for clean" happening in the migration destination manager: if the feature flag is active, invoke getOverlappingRangeDeletionsFuture and wait on it for at most rangeDeletionWaitDeadline , else keep on invoking waitForClean.