[[ Bugfix 10846 ]] Warn if password-protected stack is opened in Community Edition

The error message when opening a password-protected stack on community edition has been changed to say just that instead of reporting a corrupt stack as it did previously. The result is updated to reflect this.
Merge branch 'bugfix-10846' of https://github.com/runrevfraser/livecode into bugfix-10846
Merge branch 'bugfix-10846' into release-6.1.2