fix: add wait before first push in second scenario

The failure was at line 358 - the FIRST push in the second scenario,
not between pushes. The race condition occurs because the second
scenario reuses the same repo name from the first scenario, and
there may be a race between repo deletion completing and the new
repo being ready.

Add _wait_for_repo_ready after entering the second temporary_repo
context to ensure the new repo is in a consistent state before
the first push.

Author: The-Obstacle-Is-The-Way

tests/test_upstream_hub.py

@@ -355,6 +355,9 @@ def test_push_dataset_dict_to_hub_overwrite_files(self, temporary_repo):
         # Push to hub two times, but the second time with fewer files.
         # Verify that the new files contain the correct dataset and that non-necessary files have been deleted.
         with temporary_repo(ds_name):
+            # Wait for repo to be ready after creation (avoid race with previous repo deletion)
+            self._wait_for_repo_ready(ds_name)
+
             local_ds.push_to_hub(ds_name, token=self._token, max_shard_size=500 << 5)
 
             # Wait for Hub to fully process the first push