This update enhances the Odoo Enterprise VoIP application by enabling users to manage and conduct multiple calls simultaneously. The changes improve call handling and support features like transfers, providing a more robust and efficient communication experience. This enhancement is part of a larger effort to improve the core VoIP functionality.

This PR implements the basis of having multiple calls at the same
time in the VoIP application. This is done by refining a bit the session
management introduced here: https://github.com/odoo/enterprise/pull/104426

It also works perfectly fine with multiple transfers.

Task-4417167