Change mail_mail_statitcs tree view
CHANGELOG:
### Changed
- [#984](https://git.coopdevs.org/coopdevs/som-connexio/odoo-somconnexio/-/merge_requests/984) Change mail_mail_statitcs tree view
Related card: https://trello.com/c/i1vA86BC/1549-vista-de-correus-massius-enviats-a-un-partner
Edited by Gerard Funosas