Add tiered upsell discounts and shipping rate filters to Multi-recipient Checkout

Multi-recipient checkout updates

Merchants can now add tiered discounts to the multi-recipient checkout page:

• Add discounts based on the number of recipients in a checkout or the total product value of the send
• Discounts can be $ off, % off or free shipping
• Multiple tiers can be added for $ off and % off. For instance, 5% off after 10 recipients, 10% after 20 recipients.
• A customizable upsell message will display, prompting the shopper to add items to reach different tiers. Merchants can control when the message starts displaying based on "% of the way to next tier"

Merchants can filter specific shipping rates from displaying on the multi-recipient checkout, defining filters based on price or title.

Miscellaneous:

• Fixed incompatibility with Transcy app preventing total from updating
• Added "Fill Down" option for recipient fields to duplicate value to all recipients