Make use of `backup_borg_postgresql_databases_auto`

Related to b0c63914cb

Ref:
- https://github.com/mother-of-all-self-hosting/ansible-role-backup_borg/pull/12
- 02dd1a8d70

group_vars/matrix_servers

@@ -3137,7 +3137,7 @@ backup_borg_postgresql_databases_hostname: "{{ postgres_connection_hostname if p
 backup_borg_postgresql_databases_username: "{{ postgres_connection_username if postgres_enabled else '' }}"
 backup_borg_postgresql_databases_password: "{{ postgres_connection_password if postgres_enabled else '' }}"
 backup_borg_postgresql_databases_port: "{{ postgres_connection_port if postgres_enabled else 5432 }}"
-backup_borg_postgresql_databases: "{{ postgres_managed_databases | map(attribute='name') if postgres_enabled else [] }}"
+backup_borg_postgresql_databases_auto: "{{ postgres_managed_databases | map(attribute='name') if postgres_enabled else [] }}"
 
 backup_borg_location_source_directories:
   - "{{ matrix_base_data_path }}"