This fix addresses a security oversight in project task sharing for portal users. It restricts portal users' access to child task IDs and tag IDs fields, preventing them from viewing or modifying task hierarchies and tags they shouldn't have access to. The fix ensures consistent access control across all related fields.

Oversight in 06919a232251cbd68a28500757aef5cd2e3363a0

Need to handle `default_child_ids` and `default_tag_ids` as well.

Forward-Port-Of: odoo/odoo#153305
Forward-Port-Of: odoo/odoo#153152