Bug 35892: Populate order price using GetMarcPrice if no price specified

Bug 35892: Populate order price using GetMarcPrice if no price specified

Previously this happened after the fact, automagically, if no price was included in the order record. We should
rather load the Marc price into the order form if we don't have a price form the '...ToOrder' system preferences

To test:

Setup -- Set systempreferences below

MarcFieldsToOrder:
price: 949$g
quantity: 949$k
budget_code: 949$l
discount: 949$m
sort1: 949$n
sort2: 949$q

MarcItemFieldsToOrder:
homebranch: 949$a
holdingbranch: 949$b
itype: 949$y
nonpublic_note: 949$x
public_note: 949$z
loc: 949$c
ccode: 949$8
notforloan: 949$7
uri: 949$u
copyno: 949$t
replacementprice: 949$v
itemcallnumber: 949$o
quantity: 949$k
budget_code: 949$l

Stage the attached bib-303.marcxml file
Add to basket from the staged file
Note that item prices are populated as '6.50' from 949$g
Cancel
Update MarcFieldsToOrder and map price to "020$c"
Add to basket from the staged file
Note the price is not populated, because 020$c contains a dollar sign
Cancel
Apply patch, restart all
Add to basket from the staged file
Note the price is now correctly populated from fallback to GetMarcPrice

Note: GetMarcPrice does some automatic munging, that's why 020$c on it's own doesn't work - this could be done to fields in MarcFieldsToOrder/MarcItemFieldsToOrder but this would be an enhancement.
This bug simply restores the previous behavious, but does it on the front end and is more obvious to the user

Signed-off-by: Andrew Fuerste-Henry <andrewfh@dubcolib.org>
Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
Signed-off-by: Katrin Fischer <katrin.fischer@bsz-bw.de>