folder_branch_ops: unembed block changes when unstaging
folder_branch_ops: unembed block changes when unstaging

Otherwise the resolution put will get rejected.

Issue: KBFS-1676

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