error handling and user experience when connecting to remote storage systems

[Aditya-vegi]

Enhance error handling for storage connection issues, includ📌 Description

This PR improves error handling and user experience when connecting to remote storage systems, especially for Google Cloud Storage (GCS).

It addresses issues where users encounter failures such as:

credential propagation was unsuccessful
storage connection initialization errors
🚀 Changes Made
Added better exception handling around _init_filesystem
Improved error messaging to clearly indicate:
authentication failures
permission issues
Ensured storage_options defaults to an empty dictionary when not provided
Provided clearer guidance for users when access to restricted datasets is denied
🛠️ Code Changes
if storage_options is None:
storage_options = dict()
try:
self._fs, self._base_path = _init_filesystem(self._url, **storage_options)
except (OSError, ImportError) as exc:
raise IOError(
"An error occurred establishing a connection to the storage system. "
"This may be due to authentication failure or insufficient permissions."
) from exc
🧪 Testing
Tested in Google Colab environment
Verified behavior when:
user is not authenticated
user lacks dataset permissions
Confirmed appropriate error messages are raised
⚠️ Notes
Some datasets (e.g., MalariaGEN) require prior access approval

Users must authenticate using:

from google.colab import auth
auth.authenticate_user()
🎯 Impact
Improves debugging experience for users
Reduces confusion around authentication vs permission errors
Makes the system more robust and user-friendlying authentication errors with Google Cloud.