[FIX] purchase: fiscal position from onchange_partner_id
[FIX] purchase: fiscal position from onchange_partner_id

Used case:

-Configure admin as multi-company user
-Create 2 fiscal positions (one for company "Odoo BE" and one for company "Odoo US")
-Set admin on company "Odoo BE"
-On supplier (Asustek) configure fiscal position Odoo BE
-Set admin on company "Odoo US"
-On supplier (Asustek) configure fiscal position Odoo US
-Configure a product (Laptop E5023) with:
   *route "Buy"
   *supplier (Asustek) without company
   *reordering rules (min qty: 20, max qty: 40)
-Set admin on company "Odoo BE"
-Run scheduler via the cron

Behavior before the fix:

-Fiscal position on the created PO is the fiscal position for "Odoo BE" (and PO is for the company "Odoo US")

Behavior after the fix:

-Fiscal position on the create PO is the fiscal position for "Odoo US".

Closes #11537

opw:673288

odootr/odoo,vnsofthe/odoo,makinacorpus/odoo,Noviat/odoo,odootr/odoo,jfpla/odoo,ehirt/odoo,Nowheresly/odoo,Adel-Magebinary/odoo,microcom/odoo,dfang/odoo,ehirt/odoo,leorochael/odoo,odootr/odoo,provaleks/o8,shingonoide/odoo,sysadminmatmoz/OCB,tvibliani/odoo,ygol/odoo,laslabs/odoo,ygol/odoo,vnsofthe/odoo,dfang/odoo,glovebx/odoo,alexcuellar/odoo,NeovaHealth/odoo,BT-ojossen/odoo,vnsofthe/odoo,alexcuellar/odoo,Daniel-CA/odoo,Noviat/odoo,eino-makitalo/odoo,Nowheresly/odoo,funkring/fdoo,leorochael/odoo,Adel-Magebinary/odoo,dfang/odoo,shingonoide/odoo,microcom/odoo,shingonoide/odoo,synconics/odoo,bplancher/odoo,glovebx/odoo,provaleks/o8,Elico-Corp/odoo_OCB,OpenUpgrade/OpenUpgrade,synconics/odoo,funkring/fdoo,makinacorpus/odoo,eino-makitalo/odoo,microcom/odoo,spadae22/odoo,hip-odoo/odoo,eino-makitalo/odoo,Elico-Corp/odoo_OCB,tvibliani/odoo,tvibliani/odoo,hip-odoo/odoo,bplancher/odoo,eino-makitalo/odoo,Endika/odoo,Elico-Corp/odoo_OCB,hassoon3/odoo,makinacorpus/odoo,mustafat/odoo-1,CatsAndDogsbvba/odoo,Noviat/odoo,Nowheresly/odoo,tvibliani/odoo,synconics/odoo,laslabs/odoo,leorochael/odoo,jfpla/odoo,provaleks/o8,laslabs/odoo,Daniel-CA/odoo,makinacorpus/odoo,sysadminmatmoz/OCB,OpenUpgrade/OpenUpgrade,spadae22/odoo,Adel-Magebinary/odoo,funkring/fdoo,hip-odoo/odoo,alexcuellar/odoo,provaleks/o8,sysadminmatmoz/OCB,ygol/odoo,BT-ojossen/odoo,spadae22/odoo,Adel-Magebinary/odoo,Endika/odoo,Noviat/odoo,glovebx/odoo,Daniel-CA/odoo,Noviat/odoo,synconics/odoo,storm-computers/odoo,microcom/odoo,hassoon3/odoo,NeovaHealth/odoo,diagramsoftware/odoo,Elico-Corp/odoo_OCB,alexcuellar/odoo,glovebx/odoo,makinacorpus/odoo,leorochael/odoo,vnsofthe/odoo,storm-computers/odoo,NeovaHealth/odoo,ygol/odoo,vnsofthe/odoo,datenbetrieb/odoo,diagramsoftware/odoo,laslabs/odoo,jfpla/odoo,hassoon3/odoo,spadae22/odoo,OpenUpgrade/OpenUpgrade,leorochael/odoo,funkring/fdoo,BT-ojossen/odoo,datenbetrieb/odoo,BT-ojossen/odoo,provaleks/o8,mustafat/odoo-1,provaleks/o8,CatsAndDogsbvba/odoo,OpenUpgrade/OpenUpgrade,glovebx/odoo,makinacorpus/odoo,Daniel-CA/odoo,alexcuellar/odoo,eino-makitalo/odoo,sysadminmatmoz/OCB,eino-makitalo/odoo,hip-odoo/odoo,NeovaHealth/odoo,odootr/odoo,jfpla/odoo,spadae22/odoo,laslabs/odoo,ygol/odoo,NeovaHealth/odoo,spadae22/odoo,OpenUpgrade/OpenUpgrade,Elico-Corp/odoo_OCB,datenbetrieb/odoo,storm-computers/odoo,vnsofthe/odoo,microcom/odoo,Adel-Magebinary/odoo,OpenUpgrade/OpenUpgrade,Endika/odoo,BT-ojossen/odoo,dfang/odoo,Endika/odoo,datenbetrieb/odoo,datenbetrieb/odoo,NeovaHealth/odoo,CatsAndDogsbvba/odoo,CatsAndDogsbvba/odoo,Nowheresly/odoo,ygol/odoo,BT-ojossen/odoo,synconics/odoo,mustafat/odoo-1,diagramsoftware/odoo,synconics/odoo,Adel-Magebinary/odoo,ehirt/odoo,storm-computers/odoo,BT-ojossen/odoo,sysadminmatmoz/OCB,ygol/odoo,Elico-Corp/odoo_OCB,odootr/odoo,storm-computers/odoo,bplancher/odoo,diagramsoftware/odoo,Daniel-CA/odoo,bplancher/odoo,dfang/odoo,ehirt/odoo,CatsAndDogsbvba/odoo,glovebx/odoo,jfpla/odoo,Noviat/odoo,mustafat/odoo-1,laslabs/odoo,diagramsoftware/odoo,spadae22/odoo,shingonoide/odoo,NeovaHealth/odoo,sysadminmatmoz/OCB,provaleks/o8,jfpla/odoo,funkring/fdoo,alexcuellar/odoo,jfpla/odoo,mustafat/odoo-1,leorochael/odoo,alexcuellar/odoo,shingonoide/odoo,mustafat/odoo-1,Nowheresly/odoo,microcom/odoo,ehirt/odoo,tvibliani/odoo,tvibliani/odoo,ehirt/odoo,Nowheresly/odoo,Endika/odoo,shingonoide/odoo,storm-computers/odoo,Endika/odoo,sysadminmatmoz/OCB,synconics/odoo,hip-odoo/odoo,Noviat/odoo,hassoon3/odoo,glovebx/odoo,hassoon3/odoo,Daniel-CA/odoo,vnsofthe/odoo,makinacorpus/odoo,odootr/odoo,diagramsoftware/odoo,funkring/fdoo,eino-makitalo/odoo,Adel-Magebinary/odoo,leorochael/odoo,CatsAndDogsbvba/odoo,diagramsoftware/odoo,Endika/odoo,Nowheresly/odoo,dfang/odoo,hip-odoo/odoo,hassoon3/odoo,odootr/odoo,CatsAndDogsbvba/odoo,shingonoide/odoo,datenbetrieb/odoo,OpenUpgrade/OpenUpgrade,tvibliani/odoo,bplancher/odoo,mustafat/odoo-1,ehirt/odoo,Daniel-CA/odoo,funkring/fdoo,datenbetrieb/odoo,bplancher/odoo