Fix typo in date.range perms for group_user

CHANGELOG:

### FIXED
- [#755](https://gitlab.com/coopdevs/odoo-somconnexio/-/merge_requests/755) Fix typo in date.range perms for group_user

Related card: https://trello.com/c/7mvWkxBf/1186-error-permisos-montse-al-executar-el-balan%C3%A7-de-sumes-i-saldos

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