See also #30538
Previously the `SelectSegments` changed to clone all return value
preventing possible update to returned info.
Since meta is implemented following COW rules, this shall not happen and
any update on segment shall have copy before it.
This PR:
- Remove clone for read-only Get segment info
- Add Segment Operator abstraction for changing segment
- Implemnt COW for updating MaxRowNum
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Signed-off-by: Congqi Xia <congqi.xia@zilliz.com>
