The 'Libation blocked by Windows security' dialog is generated from
GetApplicationControlBlockedMessage, so it repeated the broken Unblock-File
command verbatim and offered a reinstall that cannot clear an Application
Control block. Explain the missing signature instead, and tell the user how to
check which mode Smart App Control is in and what turning it off costs.
Point the incomplete-upgrade message at its own docs anchor now that the two
failures have separate sections.
Tests cover the message text because it is the whole deliverable here: one
asserts Unblock-File cannot come back, one checks the blocked file and cause
are named, and one pins each message to the docs section it links to.
Refs #1967
Co-authored-by: rmcrackan <rmcrackan@gmail.com>