As the system now starts to be used by real users, we noticed a few points of improvement that can easily be done in stable and will provide a better UX when interacting with the system.

The payment proof as a field was a consequence of multiple iterations of the system; but it ended up only as a way to input the proof and nothing else.
It is confusing, only allows one proof at a time, and is overall not nice to use.
To improve that, we will remove the field and replace it with an 'Attach Payment Proof' button similar to the expense app, allowing for a better experience.

The similar rental check was checking even if all the related fields were empty. On a database migrating from a previous version, this leads to ALL the rentals to be marked as similar, which isn't ideal.
The same check was also comparing multiple rentals from the same employee as long as they are active. As rentals for an employee cannot overlap, it makes no sense to check this case and cause false positives.

task-6448054