refactor: update DiskManagerClient callers to use new GetInstance() interface Change all DiskManagerClient singleton calls from DelayedSingleton<T>::GetInstance()->Method() to DiskManagerClient::GetInstance().Method() following the Meyers' singleton refactor in disk_manager repo. Co-Authored-By: Agent Signed-off-by: zhonglufu <zhonglufu@h-partners.com> Change-Id: I4dd49e29c9066ff01e4509fdb7cce9023614a27f |