[FIX] digest: ensure cron sends all ready digests

Currently only digest planned "today" are sent. Which means that digest that
missed a cron tick are not sent anymore. We fix that by making the cron run
on all digest whose scheduled date is in the past or today.

LINKS

Task ID 2197417
PR odoo/odoo#51619

addons/digest/models/digest.py

@@ -196,7 +196,7 @@ class Digest(models.Model):
 
     @api.model
     def _cron_send_digest_email(self):
-        digests = self.search([('next_run_date', '=', fields.Date.today()), ('state', '=', 'activated')])
+        digests = self.search([('next_run_date', '<=', fields.Date.today()), ('state', '=', 'activated')])
         for digest in digests:
             try:
                 digest.action_send()