Returns a fresh reference for dataset content in Storage.
WARNING: Keep path private. Do not write it to logs.
A signed path grants direct Storage access until it expires.
Use the same authenticated user and project context for Storage access.
When signed, the scopes list shows read access or read and write access based on your permissions.
If the signer cannot create a reference, uri remains and origin, path, scopes, and expiresAt are null.
expiresAt is epoch seconds and applies to path only.
Dataset rows stay in Storage.
Requires the TestCase:Read permission.