[FIX] l10n_ch: fix translation in tax report

Wrong date, the tax change happens between 31.12.2023 and 01.01.2024.
Translation files were already correct.

closes odoo/odoo#120312

Related: https://github.com/odoo/odoo/pull/113001


Signed-off-by: Brice Bartoletti (bib) <bib@odoo.com>