Prior to this commit, the separator used to separate the names of the
members of a group DM could not be translated. This is because the
string being translated is too short to be considered by the translation
system.
This commit fixes the problem by no longer relying on the Odoo
translation system and instead using the ECMAScript Internationalization
API.
closesodoo/odoo#118306
Signed-off-by: Alexandre Kühn (aku) <aku@odoo.com>