Signed-off-by: Balaji balaji@anyscale.com

Why are these changes needed?

Users want to upload checkpoints to non-AWS S3 filesystems, but they can't.

To upload to a non-AWS S3 filesystem, you need to specify endpoint_override as a query parameter. However, Experiment.remote_checkpoint_dir behaves poorly if SyncConfig.upload_dir contains a query string:

>>> experiment = Experiment(
...         name="spam",
...         run=lambda config: config,
...         sync_config=SyncConfig(syncer="auto", upload_dir="s3://bucket?scheme=http"),
... )
>>> experiment.remote_checkpoint_dir
s3://bucket?scheme=http/spam

This PR fixes the issue by updating Experiment.remote_checkpoint_dir to parse query strings.

Related issue number

Closes #29845

Checks

• I've signed off every commit(by using the -s flag, i.e., git commit -s) in this PR.
• I've run scripts/format.sh to lint the changes in this PR.
• I've included any doc changes needed for https://docs.ray.io/en/master/.
• I've made sure the tests are passing. Note that there might be a few flaky tests, see the recent failures at https://flakey-tests.ray.io/
• Testing Strategy
  • Unit tests
  • Release tests
  • This PR is not tested :(