Werk #17392: Synthetic Monitoring: Fix environment building as non-privileged user

Robotmk can be configured to execute plans as a specific user. The standard use case is that one or more tests of a plan need access to the Windows desktop. In case the plan user was a not an administrator, building the RCC environment of the plan might have failed (if configured). The scheduler status service went CRITICAL and reported "Plan '...': Environment building failed, see service details. Plan won't be scheduled." in this case.

To the list of all Werks