25-1-4-e: Bug fixes in changefeed exports #31221

zinal merged 3 commits intoydb-platform:stable-25-1-4-enterpriseydb-platform/ydb:stable-25-1-4-enterprisefrom

stanislav-shchetinin:fix-part-cnt-bug-25-1-estanislav-shchetinin/ydb:fix-part-cnt-bug-25-1-eCopy head branch name to clipboard