[FIX] website_sale: removing compute_currency function from qweb template (#26606)

compute method called 2 times in t-esc case when monetary field has "from_currency ::
 1) value_to_html: compute method call when qweb monetary widget is return value as a html.
     see https://github.com/odoo/odoo/blob/10.0/odoo/addons/base/ir/ir_qweb/fields.py#L325
 2) compute_currency : compute_currency method is pass from controller into render engine and it is call the compute method.
So, we removed compute_currency method from qweb template in the t-esc with monetary widget.