[IMP] l10n_ca: remove unused tax template

HST 14% tax was replaced with 15% tax in October 2016 as per GST/HST
provincial rates table [1].

[1] https://www.canada.ca/en/revenue-agency/services/tax/businesses/topics/gst-hst-businesses/charge-collect-which-rate/calculator.html#rt

)

opw-2290216

closes odoo/odoo#54110

Signed-off-by: Nicolas Martinelli (nim) <nim@odoo.com>