Coupon codes assigned to a specific channel working across all channels

Describe the bug Coupon codes don't seem to be sandboxed in channels - a coupon code assigned to channel A will also apply to orders in channel B if the coupon code is the same.

To Reproduce

Create 2 channels, A & B
Switch the admin UI to channel A
Create a promotion, call it "flash-sale", action being $20 off.
Switch to channel B
Create a promo, call it "flash-sale" matching the first promo under channel A.
Note, both promotions in channels A and B have the same code.
As a client, switch to channel A (pass channel A token with GraphQL requests)
run the ApplyCoupon mutation, give it the code "flash-sale"
This will apply 2 discounts from both channels on the active order, which is not the expected behavior

Expected behavior When applying a coupon to an active order given a channel, only that coupon should be applied. Other coupon codes under different channels, even if the coupon code matches should not be applied.

Environment (please complete the following information):

@vendure/core version: 1.9.3
Nodejs version: v18.8.0
Database (mysql/postgres etc): v18.8.0

vendure-ecommerce / vendure

Coupon codes assigned to a specific channel working across all channels #2052