[OU-FIX] mail: avoid duplication error in mail_group_moderation_rel query

Author: MiquelRForgeFlow

openupgrade_scripts/scripts/mail/15.0.1.5/pre-migration.py

@@ -170,13 +170,12 @@ def migration_to_mail_group(env):
             ("mail_channel_moderator_rel", "mail_group_moderator_rel"),
         ],
     )
-    openupgrade.rename_columns(
+    openupgrade.logged_query(
         env.cr,
-        {
-            "mail_group_moderator_rel": [
-                ("mail_channel_id", "mail_group_id"),
-            ]
-        },
+        """
+        ALTER TABLE mail_group_moderator_rel
+        ADD COLUMN mail_group_id integer
+        """
     )
     # fill mail_group table
     sql.create_model_table(
@@ -234,7 +233,16 @@ def migration_to_mail_group(env):
         UPDATE mail_group_moderator_rel rel
         SET mail_group_id = mg.id
         FROM mail_group mg
-        WHERE mg.old_channel_id = rel.mail_group_id""",
+        WHERE mg.old_channel_id = rel.mail_channel_id""",
+    )
+    openupgrade.logged_query(
+        env.cr,
+        """
+        ALTER TABLE mail_group_moderator_rel
+        DROP COLUMN mail_channel_id;
+        DELETE FROM mail_group_moderator_rel
+        WHERE mail_group_id IS NULL;
+        """
     )
     # fill mail_group_moderation.mail_group_id (field is required)
     openupgrade.logged_query(