Removed unused columns in related contract tree view
CHANGELOG:
### CHANGED
- [#938](https://git.coopdevs.org/coopdevs/som-connexio/odoo-somconnexio/-/merge_requests/938) Removed unused columns in related contract tree view
Related card: https://trello.com/c/GgqwxaZG/1473-modificar-vista-tree-contractes-relacionats
Edited by César López Ramírez