Acronis Cyber Infrastructure: update from 3.0.5 to 3.5.x fails with "Cannot generate certificate: touch: cannot touch '/usr/libexec/vstorage-ui-backend/.rnd': Permission denied"

Symptoms

1. Attempt to update a cluster from 3.0.5 to 3.5.3-x version failed with 'Internal error' in UI and shortly after that cluster nodes started to be displayed as 'Offline' and cluster state is 'Unavailable' on main WebCP dashboard.

2. The following errors can be seen in logs on the Management Node revealing issues with ui-backend certificate:

/var/log/vstorage-ui-backend/software-updates.log: