`DataTypeFactory::get` locks a mutex inside shared a context, there was a case when many threads were locked inside it

https://pastila.nl/?0043b3e6/c557368f4cf0eb87a3c6f2cc162bc693

It is not clear which thread locked the mutex for a long time. However, it may be possible to lock less inside `DataTypeFactory::get`.
{
    auto lock = getLock();
    if (!shared->replicated_fetches_throttler)
        shared->replicated_fetches_throttler = std::make_shared<Throttler>(
            settings.max_replicated_fetches_network_bandwidth_for_server);
    return shared->replicated_fetches_throttler;
}
ThrottlerPtr Context::getReplicatedSendsThrottler() const
{
    auto lock = getLock();
    if (!shared->replicated_sends_throttler)
        shared->replicated_sends_throttler = std::make_shared<Throttler>(
            settings.max_replicated_sends_network_bandwidth_for_server);
    return shared->replicated_sends_throttler;
}
bool Context::hasDistributedDDL() const