Only check the lock screen order if NVDA is installed (#14487)
Summary of the issue:
NVDA can only detect the lock screen windows, and windows below the lock screen, if NVDA is installed.
When running a portable copy, or NVDA from source, locking NVDA causes an error every cache cycle due to the lock screen not being detected.
Description of user facing changes
logging/error sounds are suppressed when locking Windows and using a portable or source copy of NVDA
Description of development approach
Lock screen z-order is only checked if the current running version of NVDA is installed.
