Open order : Incorrect piece creation for non-package P/E mixed order line

Purpose/Overview:
Open order flow : Support holding reference for piece in P/E mixed line.

Requirements/Scope:
1. Given
Mixed non-package POL with Location element in the POL contains only holding reference
Create inventory for electronic "None/Instance"
Create inventory for physical "Instance_Holding/Instance_Holding_Item"
UI sent Location with holding reference
Manual create piece is false

Then
Actual :
Electronic piece is created without holding and location reference
Physical piece is created with holding
Expected:
Should we create electronic piece with location from holding? Yes
If yes, then there are to options How location element can look:
1. Both holding and location reference in the one location element
Seems like it is not supportable on UI and back-end.
2. On UI side split on back-end side original location on two : first with location reference for electronic and second for physical with holding reference for physical.
Seems like it is not supportable on UI. On back-end side will be processed in correct way.
3. Always split on back-end side original location on two : first with location reference for electronic and second for physical with holding reference for physical.
Seems like supportable on UI and need changes for back-end.

2. Given
Mixed non-package POL with Location element in the POL contains only location reference

Create inventory for electronic "None/Instance"
Create inventory for physical "Instance_Holding/Instance_Holding_Item"
UI sent Location with holding reference
Manual create piece is false

Then
Actual :

Electronic piece is created with location reference
Physical piece is created with holding reference that was created for the selected location
Expected:
Same questions Still thinking approach number 3

Approach:

Always split on back-end side original location on two : first with location reference for electronic and second for physical with holding reference for physical.
Seems like supportable on UI and need changes for back-end.

Acceptance criteria:

• Logic updated

• Unit tests fixed :

• org.folio.rest.impl.PurchaseOrdersApiTest#testDateOrderedIsNotSetForPendingOrder

• org.folio.rest.impl.PurchaseOrdersApiTest#testPostListedPrintSerialInOpenStatus

• org.folio.rest.impl.PurchaseOrdersApiTest#testPutOrdersByIdPEMixFormat

• org.folio.rest.impl.PurchaseOrdersApiTest#testPostOpenOrderInventoryUpdateWithOrderFormatOther

• org.folio.rest.impl.PurchaseOrdersApiTest#testPutOrdersByIdToChangeStatusToOpen

• org.folio.rest.impl.PurchaseOrdersApiTest#testPutOrdersByIdTotalPiecesEqualsTotalQuantityWhenCreateInventoryIsFalse