azure-ai-ml: upload_directory silently swallows upload errors when show_progress=False

### Summary `azure.ai.ml._utils._asset_utils.upload_directory` silently swallows worker upload failures when `show_progress=False`, so a directory upload can fail without raising, leaving a partial/incomplete upload in remote storage while callers proceed as if it succeeded. ### Package - **Name:** azure-ai-ml - **File:** `sdk/ml/azure-ai-ml/azure/ai/ml/_utils/_asset_utils.py` - **Function:** `upload_directory` ### Root cause Files are uploaded via a `ThreadPoolExecutor`. Exceptions raised inside a worker (`upload_file`) are captured on the `Future` and only re-raised when `future.result()` is called. That call currently lives **only** inside the `if show_progress:` branch: ```python with ThreadPoolExecutor(max_workers=num_cores) as ex: futures_dict = { ex.submit(upload_file, ...): (src, dest) for ... } if show_progress: with tqdm(...) as pbar: for future in as_completed(futures_dict): future.result() # only reached when show_progress=True pbar.update(...) # when show_progress=False, .result() is never called -> exceptions swallowed ``` When `show_progress=False`, no one calls `future.result()`. The executor's `shutdown(wait=True)` waits for the threads to finish, but the stored exceptions are never observed, so `upload_directory` returns normally as if the upload succeeded. ### Expected behavior Upload errors should propagate regardless of the `show_progress` value. ### Actual behavior With `show_progress=False`, upload errors are silently ignored and the function returns `None` (apparent success). ### Fix Observe all futures (call `future.result()`) even when progress is disabled. Fixed in PR #48242.