[FIX] l10n_au: don't duplicate tax repartit° lines when upgrade

We don't duplicate the tax repartition lines
when upgrading the account module

Steps:

- Create a company with l10n_au installed
- Upgrade account module
- Create a second company
- Try to link it with Australian accounting
-> ValidationError: Invoice and credit note repartition
should each contain exactly one line for the base.

We remove the records before creating them again,
like we do in l10n_be/data/account_tax_template_data.xml

opw-2862296

closes odoo/odoo#92873

Signed-off-by: Florian Gilbert (flg) <flg@odoo.com>