[API] `skip_reconfirmation` as no effect
### Summary
It seems the optional parameter `skip_reconfirmation` has no effect when passed to user modification call.
### Steps to reproduce
Doing a CURL call such has:
```curl
curl -X PUT \
'http://git.harmonycms.net:10080/api/v4/users/6?private_token=?' \
-H 'Cache-Control: no-cache' \
-H 'Content-Type: application/x-www-form-urlencoded' \
-H 'Postman-Token: df3b33f0-ef5a-9c40-c292-c03a5e6ed6b7' \
-d skip_reconfirmation=true
```
### What is the current *bug* behavior?
The value `confirmed_at` stays to **null**.
### What is the expected *correct* behavior?
It's suppose to take a DateTime right?
issue