[WIP] gs: fix import-url for directories

[dtrifiro]

fixes #7638

[daavoo]

We should be catching this external data stuff in the cloud tests (https://github.com/iterative/dvc-gs).
Seems that we are not really testing external data at all?
Similar thing happened in #7563

[efiop]

@daavoo Indeed, we specifically skip import_dir test in https://github.com/iterative/dvc-gs/blob/564592e28be38c8d45f7c04f0b07d0065a65f1b2/dvc_gs/tests/test_dvc.py#L39 I think this is for legacy reasons from way back when we used etags for dir hashes. We now use regular md5s, so might be able to make it work for gs.

[efiop]

@dtrifiro The testing for gs is a bit complicated, because we are in the middle of creating plugins, so the tests run in https://github.com/iterative/dvc-gs (they have the creds and stuff there). If you don't happen to have set it up before, you could create a test PR in dvc-gs and make it install dvc from your fork and run the tests there, just to confirm that it works before merging this.

[dtrifiro]

Seems there are some failures. Will mark this PR as draft and investigate later

[dberenbaum]

We should be catching this external data stuff in the cloud tests (https://github.com/iterative/dvc-gs).
Seems that we are not really testing external data at all?
Similar thing happened in #7563

Should we create a separate issue for this?

[daavoo]

This needs to be moved to https://github.com/iterative/dvc-objects

[dtrifiro]

Closing this as this was merged in treeverse/dvc-objects#41. Just need to wait for dvc-data to be bumped