Adding item after clearing suppliers can be blocked

[XenonShawn]

Clearing suppliers and then trying to add an item that already exists results in an error that the item from a different supplier already exists, even though such a supplier is not in the list.

Medium severity as it causes inconvenience to the user, but user can still continue using the product.

[soc-se-bot]

Your response not required for this bug as the team has accepted the bug as it is.