bug: flaky TestTopicStreamReaderImpl_ReadMessages

[asmyasnikov]

https://github.com/ydb-platform/ydb-go-sdk/actions/runs/7369443024/job/20054768261#step:4:65

--- FAIL: TestTopicStreamReaderImpl_ReadMessages (3.73s)
    --- FAIL: TestTopicStreamReaderImpl_ReadMessages/BufferSize (2.67s)
        stream_reader_impl_test.go:457: 
        --- FAIL: TestTopicStreamReaderImpl_ReadMessages/BufferSize/DecrementIncrementBufferSize (1.[66](https://github.com/ydb-platform/ydb-go-sdk/actions/runs/7369443024/job/20054768261#step:4:67)s)
            panic.go:661: test run counter: 55
            testing.go:11[69](https://github.com/ydb-platform/ydb-go-sdk/actions/runs/7369443024/job/20054768261#step:4:70): test executed panic(nil) or runtime.Goexit: subtest may have called FailNow on a parent test
FAIL