Document image requests now use the intended unique identifier instead of an unnecessary signature value. This helps keep document image links consistent and avoids issues caused by using the wrong parameter.

This commit removes the unnecessary usage of signature instead of
unique in the route params for documents/image.

A leftover debugging statement was removed from the Data Cleaning feature. This prevents accidental interruptions during normal use and keeps the feature running smoothly.

TaskID: 2240275

Subscription renewals and manual invoice generation now keep start and end dates consistent, preventing invoices from being created beyond fixed contract periods. This reduces billing confusion for users and improves demo data so subscription workflows behave more realistically.

Before  this commit:
 * Field "date" is wrong when you do a renewal subscription
    It is wrongfully set to the invoice end period. 
 * Button "generate invoice" modifies the end date (date of today)
 * When the template is 'fixed period', the generate invoice button allow to generate invoices after the end date. 
 * The start button was confusing on closed subscriptions.

Taskid: 2168496