Processes a tenant exit by setting the exit date on a profile contract.

A profile contract represents the link between a tenant (profile) and a leasing contract,
including their share of rent and their entry/exit dates.

This endpoint allows you to record when a tenant is leaving the property by setting
the exit_date on their profile contract. The exit_date must be after the entry_date.

Optionally, you can attach an amendment document (avenant) by providing a URL to the file.
The amendment will be automatically stored in the tenant's document directory structure.

Parameters:

• exit_date (required): The date the tenant will exit the property. Must be after entry_date.
• amendment_url (optional): URL to an amendment PDF document to attach to the contract.

Validation:

• The exit_date must be after the tenant's entry_date
• If an amendment_url is provided, the file must be downloadable and valid