[FIX] web: propagate context for pivot view fields
[FIX] web: propagate context for pivot view fields

On the "+" in the pivot views to group by given fields, these field were
not translated in the user choosen language.

closes #8656
opw-649918

dfang/odoo,sysadminmatmoz/OCB,hip-odoo/odoo,laslabs/odoo,laslabs/odoo,laslabs/odoo,syci/OCB,ygol/odoo,storm-computers/odoo,syci/OCB,sysadminmatmoz/OCB,microcom/odoo,microcom/odoo,optima-ict/odoo,stephen144/odoo,dfang/odoo,microcom/odoo,microcom/odoo,ygol/odoo,Elico-Corp/odoo_OCB,bplancher/odoo,sysadminmatmoz/OCB,bplancher/odoo,sysadminmatmoz/OCB,Elico-Corp/odoo_OCB,ygol/odoo,stephen144/odoo,hip-odoo/odoo,storm-computers/odoo,optima-ict/odoo,sysadminmatmoz/OCB,Elico-Corp/odoo_OCB,syci/OCB,storm-computers/odoo,laslabs/odoo,bplancher/odoo,syci/OCB,laslabs/odoo,ygol/odoo,laslabs/odoo,optima-ict/odoo,storm-computers/odoo,ygol/odoo,Elico-Corp/odoo_OCB,ygol/odoo,bplancher/odoo,sysadminmatmoz/OCB,syci/OCB,optima-ict/odoo,syci/OCB,Elico-Corp/odoo_OCB,optima-ict/odoo,storm-computers/odoo,bplancher/odoo,dfang/odoo,stephen144/odoo,ygol/odoo,stephen144/odoo,storm-computers/odoo,sysadminmatmoz/OCB,hip-odoo/odoo,hip-odoo/odoo,optima-ict/odoo,microcom/odoo,hip-odoo/odoo,dfang/odoo,hip-odoo/odoo,microcom/odoo,bplancher/odoo,stephen144/odoo,stephen144/odoo,dfang/odoo,Elico-Corp/odoo_OCB,dfang/odoo