DVCFileSystem repo factory property returns incorrect value when repo is set

DVCFileSystem repo factory property returns incorrect value when repo is set: a task in harbor-swesmith-rl-artifacts: Harbor SWE-Smith 强化学习数据产物 (Harbor dataset). I noticed an issue with the repo factory property in the DVCFileSystem class. The behavior changes depending on how the filesystem is…

The task

I noticed an issue with the `repo_factory` property in the `_DVCFileSystem` class. The behavior changes depending on how the filesystem is initialized.

Part of keryszhan/harbor-swesmith-rl-artifacts.