[FIX] l10n_es: check if chart of account is installed in migration

In last added migration script in https://github.com/odoo/odoo/commit/b40216a8ae8fefd03311b2884e7b83644baac0a1

, the code assumes the chart of account of l10n_es is installed. But happens that you may have installed several l10n_* modules, including l10n_es, but not having the chart of l10n_es installed (you have installed the chart of another module).

In this case, then the update crashes because tax_ids is None and tuple(tax_ids) crashes!

closes odoo/odoo#78958

Signed-off-by: Olivier Colson <oco@odoo.com>