[16.0] sale_tier_validation: Can't confirm order

[michaelslade54]

Module

sale_tier_validation

Describe the bug

Cannot send a quotation or confirm the order once the sales order has been validated by the reviewer. This makes the module unusable.

To Reproduce

Affected versions: v16, v15

Replicated on runboat.

Steps to reproduce the behavior:

1. Create a new tier validation for referenced model Sales Order for total > 0.
2. Create a sales order with any product, ensuring the total price is > 0.
3. Request Validation on the Sales Order.
4. Validate the tier review in the Sales Order.
5. Attempt to confirm the order or send the quotation by email. A Validation Error occurs stating the operation is under validation.

Expected behavior
Sale order state should advance to either quotation sent or sales order once the validations are complete.

Additional context
There appears to be a known issue in the OCA/server-ux repository, however as far as I can tell this is the only module relying on base_tier_validation that currently experiences this issue. It may require a custom fix per module.

Note: If the user is the same one required to validate, and the user simply clicks Confirm Order, then the module performs as intended.