[FIX] mail: fix missing recipient data

Use case
--------
If the a user has partner_share set to NULL not to 'false'
he will not receive any notification

The orm consider False and NULL value as False for boolean field,
the query that fetch the recipient data should have a consistent
behavior

closes odoo/odoo#117083

X-original-commit: a50fbd1f9404fd05eb576474eb3d10c94d37aa52
Signed-off-by: Thibault Francois <tfr@odoo.com>
Signed-off-by: Thibault Delavallee (tde) <tde@openerp.com>

addons/mail/models/mail_followers.py

@@ -158,7 +158,7 @@ class Followers(models.Model):
            sub_followers.is_follower as _insert_followerslower
       FROM res_partner partner
       JOIN sub_followers ON sub_followers.pid = partner.id
-                        AND (NOT sub_followers.internal OR NOT partner.partner_share)
+                        AND (sub_followers.internal IS NOT TRUE OR partner.partner_share IS NOT TRUE)
  LEFT JOIN LATERAL (
         SELECT users.id AS uid,
                users.share AS share,