issue: #36293#36242
pr: #36549
after qn recover, delegator may be loaded in new node, after all segment
has been loaded, delegator becomes serviceable. but delegator's target
version hasn't been synced, and if search/query comes, delegator will
use wrong target version to filter out a empty segment list, which
caused empty search result.
This pr will block delegator's serviceable status until target version
is synced
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Signed-off-by: Wei Liu <wei.liu@zilliz.com>