Handle returned loan prep for consolidated COG

[CarolineDenis]

When creating a loan, gift, or similar transaction using a prep from a CO that belongs to a consolidated COG, all of its sibling preps are automatically added to the interaction and will be deleted along with it if the interaction is deleted.

We need to apply the same logic when returning the loan.

After the loan is created and the user opens the "Return Loan" dialog, once a prep is selected and the user clicks "Apply," all of the prep's sibling preps will be returned as well.

[CarolineDenis]

NOTES:

• needs to be handle during the loan save