fix flap test: wait for closing execQuery stream from server#243

KirillKurdyukov merged 2 commits intomainydb-platform/ydb-dotnet-sdk:mainfrom

dev-fix-flaps-in-ado-net-testsydb-platform/ydb-dotnet-sdk:dev-fix-flaps-in-ado-net-testsCopy head branch name to clipboard