Description of problem:
The key UserSessionTimeOutInterval for engine-config is used to set timeout interval in minutes, after which inactive user sessions expire.
It doesn't take effect for VM Portal, but works perfectly for Administrator Portal.

Version-Release number of selected component (if applicable):
4.2.7

How reproducible:
always

Steps to Reproduce:
1. engine-config --set  UserSessionTimeOutInterval=1
2. systemctl restart ovirt-engine
3. in 2 annonymous windows log into VM portal and Administrator Portal
4. Wait more than 1 minute and see that the user is logged out from Admin but not VM Portal

Actual results:
User in VM Portal is never logged out

Expected results:
the parameter takes effect for both Portals

Additional info:
Most likely the difference is due to the fact that in ovirt-web-ui we have JS frontend and there are perdiocal REST API requests, while in Admin Portal it is handled in a different way? Maybe we should resolve it providing some counter/observer in ovirt-web-ui? 

Justification from a customer why it is a bug:

"From the perspective of the user and the administrator:
- one product feature has been lost
- the behavior is no longer consistent to the documentation
- there is a big security risk because the VM_Portal remains logged in. 

Since the VM portal is hidden when the console is opened, the user does not log off the portal while working with his VM.
As a result, hundreds of VM portals remain active throughout the day and noticeably burden the RHV management server.
This is what I can notice during my work on Management-Portal. "