[FIX] mail: can't open mail composer on virtual event
[FIX] mail: can't open mail composer on virtual event

In the case of a chatter on a calendar virtual event, there was a number
of issue because the record ID was of the type "[REAL ID]-[VIRTUAL ID]".

This caused issue when fetching and posting message with the composer.

opw-744405
closes #17179

ygol/odoo,hip-odoo/odoo,hip-odoo/odoo,ygol/odoo,ygol/odoo,ygol/odoo,hip-odoo/odoo,ygol/odoo,hip-odoo/odoo,hip-odoo/odoo,hip-odoo/odoo,ygol/odoo,ygol/odoo