You want to delegate a permission to users who can only access Email Quarantine for Administrators under the Email Security.Cloud portal.
Email Security.cloud
Create the user with limited roles under Dashboard > Administration > User Management.
Use standard role and add the following:
Once done, the User Roles will look as follow:
To view quarantined messages, you must have View Configuration and View Statistics permissions for the Administrator Quarantine service.
To release or rescan quarantined messages, you must have Edit Configuration permissions for the Administrator Quarantine service.