folder_update_prepper: don't include rmOps unrefs twice in MD
folder_update_prepper: don't include rmOps unrefs twice in MD

If the unref'd ptr is already included in `newOps`, there's no reason
to also unreference it again in `resolutionOp`.  When removing
directories, this previously resulted in the same pointers being
archived twice as part of the resolution.

Issue: KBFS-3966

keybase/client,keybase/client,keybase/client,keybase/client,keybase/client,keybase/client,keybase/client,keybase/client,keybase/client,keybase/client,keybase/client,keybase/client