Only check the lock screen order if NVDA has UIAccess (#14511)
Fixup of #14487
Summary of the issue:
NVDA can only detect the lock screen windows, and windows below the lock screen, if NVDA has UI Access.
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.
#14487 checked installation status., but checking UIAccess is a more accurate approach.
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 has UIAccess (e.g. is installed normally).
