Update User Roles
Replace a user's roles.
This endpoint allows administrators to replace the roles assigned to a user.
The roles can be scoped to a specific context (e.g., dataset or system).
If a context is provided, the roles will only be replaced within that context.
If no context is provided, all roles (system-level and dataset-level) will be replaced.
To replace roles at the system level, use the "system" context.
To replace roles at the dataset level, use the "dataset:{dataset_id}" context.
